A  PRACTICAL  TREATISE 


ON  THE  MANUFACTURE  OF 


-  STARCH,  GLUCOSE,  STARCH-SUGAR, 
AND  DEXTRINE.  • 


BASED  ON  THE  GERMAN  OF 


LADISLAUS  VON  WAGNER, 

PROFESSOR  IN  THE  ROYAL  TECHNICAL  HIGH  SCHOOL,  BUDA-PEST,  HUNGARY, 


AND  OTHER  AUTHORITIES, 

BY  JULIUS  FRANKEL, 

GRADUATE  OF  THE  POLYTECHNIC  SCHOOL  OF  HANOVER. 


EDITED  BY  ROBERT  HUTTER, 

CHEMIST,  PRACTICAL  MANUFACTURER  OF  STARCH-SUGAR  ;    PROPRIETOR  OF  THE 
PHILADELPHIA  STARCH-SUGAR  WORKS. 


Illustrated  by  58  engravings,  covering  every  branch  of  the  subject ;  including 
examples  of  the  most  recent  and  best  American  machinery. 


HENRY  CAREY  BAIRD  &  CO., 

INDUSTRIAL  PUBLISHERS,  BOOKSELLERS,  AND  IMPORTERS, 

810  WALNUT  STREET, 

LONDON:  E.  &  F.  N.  SPON,  46  CHARING  CROSS. 
1881. 


COPYRIGHT  BY 
HENRY    CAREY   BAIRD   &    CO 

1881. 


COLLINS,     PRINTER, 


PREFACE. 


THE  sudden  and  unexpected  death  of  JULIUS  FRANKEL,  while 
this  volume  was  passing  through  the  press,  renders  it  proper 
that  some  notice  should  be  made  of  him  in  this  place.  Mr. 
Frankel  was  born  at  Hildesheim,  Hanover,  Germany,  August 
26,  1831;  was  educated  under  the  eminent  Dr.  Karl  Kar- 
marsch,  at  the  Polytechnic  School  in  the  city  of  Hanover; 
came  to  the  United  States  in  1850,  and  died  in  Philadelphia, 
April  28,  1881.  He  was  a  learned,  an  industrious,  and  an 
amiable  man,  thoroughly  vgrtsed-  in  several  languages,  and  a 
good  technical  scholar,  who  was  well  acquainted  with  the 
literature  of  this  special  branch  of  knowledge.  It  need 
hardly  be  said  that  such  a  man  was  of  incalculable  value 
to  an  industrial  publishing  house.  He  had  done  other  and 
good  work  for  us,  was  thoroughly  appreciated  by  us,  as  well 
personally  as  professionally,  and  we  had  looked  forward  with 
satisfaction  to  his  future  usefulness  to  us.  Our  relations  were 
so  far  agreeable  to  him  that  they  seemed  to  infuse  into  him 
new  life,  energy,  and  hope,  when,  unhappily,  he  was  suddenly 
stricken  by  the  disease  which  in  a  few  days  brought  to  an  end 
his  useful  career.  To  us  his  loss  is  very  great ;  to  his  family  it 
is  indeed  overwhelming  and  irreparable.  It  affords  us  a  melan- 
choly satisfaction  to  pay  this  slight  tribute  to  his  worth. 

The  volume  now  presented  to  American  readers,  is  upon  a 
class  of  industries  which  has  been  surrounded  by  more  mys- 
tery than  probably  any  others  of  recent  years.  This  has  been 
so  studied  and  persistent  that  not  only  has  access  to  facto- 
ries been  barred  to  all  but  workmen,  but  even  the  inventors 
and  manufacturers  of  the  necessary  machinery  have  refused  to 
furnish  drawings  of  the  machines.  This  work,  which  is  the 


VI  PREFACE. 

only  one  on  the  subject  ever  published  in  the  English  language, 
is  mainly  based  upon  that  of  Professor  Ladislaus  von  Wagner, 
of  Buda-Pest,  Hungary,  the  very  best  book  which  has  appeared 
in  Europe,  and  which  was  really  undertaken  with  a  view  to 
advance  and  improve  a  group  of  industries,  which  had  suffered 
from  mystery,  secret  processes,  and  empiricism,  and  the  lack 
of  progress,  which  are  inseparable  from  such  modes  of  pro- 
cedure in  any  industry.  Among  those  who  with  particular  libe- 
rality assisted  Prof.  Wagner  may  be  named  Mr.  Fr.  Anthon, 
of  Prague,  Bohemia,  the  manufacturer  of  the  purest  and  finest 
starch-sugar  which  is  made  in  the  world. 

The  present  treatise  was  prepared  with  great  care,  intelli- 
gence, and  zeal  by  the  late  Mr.  Frankel,  and  it  has  been  criti- 
cally and  conscientiously  edited  by  Mr.  Robert  Hutter,  of  this 
city,  who  is  eminently  qualified  for  the  work  as  well  by  his 
education  as  by  his  present  profession  of  manufacturer  of 
starch-sugar.  It  is  now  submitted  to  the  American  public 
with  entire  confidence  in  its  being  a  thoroughly  practical  and 
valuable  addition  to  industrial  literature. 

H.  C.  B. 

PHILADELPHIA,  May  21,  1881. 


CONTENTS. 


SECTIOX  I. 

THE  CHEMISTRY  OF  STARCH. 

PAGE 

INTRODUCTORY   .                           17 

The  history  of  starch 17 

APPEARANCE  AND  VALUE '.17 

Starch  extensively  diffused  throughout  the  vegetable  kingdom           .  1 7 
Tlie  conditions  necessary  to  render  the  separation  of  starch  remune- 
rative ;  products  that  yield  commercial  starch       .         .         .         .18 
Value  and  percentage  of  starch  contained  in  various  grains  and  pota- 
toes ;  hydroscopic  water  contained  in  starch  yielding  grains  and 

potatoes 19 

FORMATION,  SUBSTANCE,  AND  NATURE  OF  STARCH  .         .        .        .19 

Investigations  of  Xaegeli  on  the  formation  and  growth  of  starch-granules  21 
Observations  of  Schleiden  on  the  strata  of  starch-granules  ;  granulose, 
starch  cellulose,  or  fibrin,  xylodin,  pyroxilin  ;  Berzelius  on  the  two 

different  forms  of  fibrin  in  plants          ......  22 

PHYSICAL  PROPERTIES 23 

Organization,  structure,  form,  and  size 23 

CHEMICAL  PROPERTIES  v 24 

The  more  immediate  ingredients  of  starch  .....  24 
The  relations  of  starch  to  warmth,  water,  acids,  bases,  alkalies,  and 

diastase       ...........  25 

Observations  of  Vogel  on  starch  boiled  in  water;  pearly  lustre  for 

bookbinders 26 

The  relations  of  starch  to  water  ;  difference  in  the  stiffening  power  of 

various  starches •  .  27 

Saussure  on  the  transformation  of  starch  paste  into  gum  and  other 

products ;  relation  of  starch  to  acids 28 

Relation  of  starch  to  diastase,  gluten,  and  animalic  liquids,  etc.  .  29 

Relation  of  starch  to  bases  and  alkalies ;  ammonia  ....  30 
Relations  of  starch  to  iodine,  bromine,  and  chlorine  .  .  .31 

Fermentation  and  decay 32 


yiil  CONTENTS. 

SECTION  II. 

THE  TECHNOLOGY  OF  STARCH,  THE  MANUFACTURE  OF  STARCH. 


PAGE 


GENERAL  INTRODUCTION    . 34 

THE  MANUFACTURE  OF  POTATO-STARCH   .         .         .         .  .38 

THE  RAW  MATERIAL .39 

The  average  chemical  composition  of  good  potatoes ;  determining 
the  amount  of  starch  in  potatoes  ....  .40 

Fresenius  and  Schulze's  method  of  determining  the  specific  gravity 
of  potatoes  .  .  .  .  ...  •  •  •  .41 

Table  for  ascertaining  the  specific  gravity  of  potatoes,  founded  on 
the  degrees  indicated  by  the  saccharometer ;  Fesca's  scale  for 
determining  the  specific  gravity  of  potatoes  .  .  .  .  .43 

THE  MANUFACTURE  OF  POTATO- STARCH   .  .47 

The  older  method  ;  Voelker's  process      .  47 

The  cleaning  of  the  potatoes  ;  Venuleth's  washing  machine  .  .41) 
Grinding  (grating)  of  potatoes  ;  Champonnois's  grater  .  .  .52 
The  operation  of  washing  (sifting)  ;  separation  of  the  starch  from 

the  paste 52 

Cylinder  sieve  with  brushes,  Seeles  &  Co.  constructors     .         .         .       55 
Siemens' s  bolting  sieve  of  latest  construction    .....        56 

The  edulcoration  and  refining  process ;  tank.s  or  walled-in  cjsterns 
(sedimenteurs)    ..........       58 

The  starch  washing  tank  (laveur) ;  Markl's  apparatus  for  measur- 
ing the  height  of  the  starch  strata  in  the  tank       .          .          .          .59 

Another  method  for  cleaning  the  impure  starch  ;  inclined  plane  (elu- 
triating machine)         .          .          .         .         .          .         .          .          .61 

Fesca's  refining  centrifugues   ........       65 

Seele's  centrifugal  drying  machine  .          .          .          .         .  70 

The  bleaching  of  starch  .          .          .  .          .          .          .  »71 

Leuchs's  bleaching  water ;  the  drying  process  .         .          .  73 

Hall's  process  for  extracting  the  yellow  pigment  from  starch  .  .  72 
Drying  chambers ;  the  drying-room  or  starch-kiln  of  Lacambre  and 

Persac         .         .          . 74 

The  yield  of  starch  from  potatoes  and  their  pulp  .  .  .  .  76 
The  manufacture  of  potato-flour ;  protein  compounds  .  .  .77 

THE  MANUFACTURE  OF  WHEAT-STARCH    ....         .         .  78 

The  raw  material    ..........  78 

Hard,  glassy,  or  steel-like  wheat ;  soft  or  white  wheat ;  semi-hard, 

or  medium  soft  wheat  .          .          .         .          .         .          .          .79 

Red  and  white  wheat ;  the  inner  structure  of  the  wheat  grain  .  .  80 
The  germ  or  embryo  ;  the  amount  of  water  in  air-dryed  wheat ;  the 

amount  of  starch  in, wheat ;  quantity  of  gluten  in  wheat         .         .  81 


CONTENTS.  IX 


The  amount  of  gum  in  -wheat ;  the  amount  of  alkalies  in  wheat ; 
amount  of  water  in  wheat ;  chemical  composition  of  wheat ;  wheat- 
starch  and  potato-starch,  difference  in  the  appearance  of  .82 
Glutinous  starch;  the  production  of  starch  from  wheat     .         .     '    .       83 
The  oldest  method ;  a  modification  of  this  method  .         .          .         .84 

Other  methods  ;  method  of  acetous  fermentation     ....       85 

Steeping  and  bi-uising  of  the  wheat ;  steeping  troughs       ...       86 
Bruising  mill  or  grain  crusher  .......       89 

The  fermentation  of  the  bruised  ground  wheat         .         .         .         .91 

Duration  of  the  fermenting  process  ;  mechanical  process  during  fer- 
mentation .          .         .         .         .         .          .         .         .         .         .92 

Effect  of  the  acids  and  ensuing  purification  upon  the  gluten  .  .  93 
The  grinding,  bruising,  or  crushing ;  Allsopp's  malting  mill  .  .  94 
Separating  the  starch  from  the  fermented  mass  ;  a  washing  drum  .  96 
The  refining  of  raw  starch  ........  99 

Depositing  troughs  .          .         . 102 

The  raw  starch  centrifugal  machine         .          .         .          .         .         .104 

The  process  of  drying     .    •      .         .         .         .         .         .         .          .105 

Method  without  fermentation  .         .          .         .         .         .         .107 

THE  MANUFACTURE  OF  WHEAT  INTO  STARCH  WITHOUT  GRINDING 

THE  WHEAT      .         .         .         .         .         .         .         .  .108 

Fesca's  washing  apparatus      .         .         .         .         .         .         .         .109 

THE  MANUFACTURE  OF  WHEAT-FLOUR  INTO  STARCH        .         .         .110 
Martin's  method ;  Martin's  washing  apparatus         .          .         .          .110 
Polaillon's  and  Maillard's  process;  Fesca's  new  method  with  the 
centrifugal  apparatus  without  kneading  the  dough — its  great  im- 
portance     . 114 

PRODUCING  STARCH  ON  A  SMALL  SCALE  FOR  DOMESTIC  USE      .        .115 
Special  methods  for  refining  and  bleaching  of  wheat-starch        .         .      116 
Nash's  application  of  ammonia  for  removing  gluten  from  wheat- 
starch          117 

Hall's  process  Vor  extracting  yellowish  pigment,  by  the  application 
of  chloride  of  lime  ;  Tucker's  process  of  purifying   starch  with 
Glauber's  salts    .         .  .         .         .         .         .         .         .     118 

Martin's  method  of  freeing  starch  from  foreign  admixtures;  Kirch- 
hoflPs  method  for  refining  gluten  containing  wheat-starch  ;  Leuchs's 
method  for  removing  gluten  from  wheat-starch  .  .  .  .119 

THE  MANUFACTURE  OF  CORN-STARCH  (MAIZE-STARCH)   .         .         .     120 

Varieties  of  maize  or  Indian  corn  ;  analyses  of  Indian  corn       .         .     120 

Anatomical  structure  and  qualitative  chemical  condition  of  maize      .     121 

First  experiments  in  making  corn-starch  ;  practical  process  ;  process 

for  manufacture  of  the  finer  quality      .         .         .         .         .         .122 

AVatts'  s  process  ;  Le  Conte's  latest  method      .         .         .         .         .123 


X  CONTENTS. 

PAGE 

Description  of  Erkenbrecher's  establishment  in  Cincinnati,  Ohio      .     124 
Glen  Cove  Co.,  N.  Y.,   Duryea's   maizena  ;    Huntley  &  Palmer, 
Reading,  England ;  corn-starch  manufactory  of  Brown  &  Poison, 
Paisley,  Scotland V        .126 

THE  MANUFACTURE  OF  RICE-STARCH  .  .  .  .  •  ,  ^  .  127 
Rice;  analysis  of  rice  by  .Payen  ;  analysis  of  ashes  of  rice  .  .127 
The  nourishing  qualities  of  rice  ;  contents  of  starch  in  rice  ;  Orlando 

Jones's  process  for  manufacturing  starch  from  rice  .  .  .128 
Ransford's  process  .  .  .  ...  .  .  .  .131 

Burger's  process 132 

Colman's  process ;  American  method 133 

Buildings  used  by  American  rice-starch  manufacturers  .  .  .134 
Rehe's  method  ;  other  grains  and  plants  from  which  commercial 

starch  is  produced 137 

DISCERNMENT  AND  DETERMINATION  OF  THE  VARIOUS   KINDS  OF 

STARCH 138 

Classification  of  the  various  kinds  of  starch  as  to  their  forms  and 
sizes ;  wheat-starch,  potato-starch,  rice-starch,  maize-starch,  the 
wheat-starch  of  commerce  .  .  .  .  .  .  .  .139 

To  distinguish  between  wheat-starch  and  potato-starch,  action  of 
chemicals  on  wheat-starch  ;  commercial  potato-starch  .'  .  .140 

Action  of  chemicals  on  potato-starch  ;  further  characteristics  of  wheat- 
and  potato-starch  ;  the  stiffening  power  of  wheat-starch  greater 
than  potato-starch  .  .  .  .  .  .  .  .  .141 

Wheat-starch  preferable  to  potato-starch  ;  temperatures  at  which  the 
paste  formations  of  wheat-  and  potato-starch  take  place ;  great 
stiffening  power  and  uniformity  of  corn- starch  .  .  '.  .  142 

Action  of  iodine  vapors  on  different  kinds  of  starch  and  flour ;  Gob- 
ley's  method  of  testing  starch  .......  143 

Mayet's  experiments  on  the  action  of  caustic  potash  on  various  kinds 

of  starch  ...........  144 

QUALITY,  TEST  AS  TO  THE  IMPURITIES  AND  ADULTERATIONS  CON- 
TAINED IN  STARCH  .         .         .         ...         .         .         .         .     144 

The  amount  of  fixed  water  in  starch        .         .         .         .         .         .144 

Scheibler's  method  of  ascertaining  the  contents  of  water  in  starch     .     145 
Table  for  ascertaining  the  contents  of  water  in  starch ;  Scheibler's 
hydrometer         .         .         .    _ ,.  .         .    .  '  .         .         .      '  v         .     146 

Block's  feeulometer ;  testing  the  starch  as  to  its  impurities,  with  refe- 
rence to  adulterations  ;  experiments  for  testing  the  adulterations  of 
starch  by  means  of  Gobley's  iodine  reaction  ....  147 

APPLICATION  OF  STARCH .'  .        .     150 

Tabular  synopsis  of  the  various  operations  necessary  to  the  manufac- 
ture of  starch  .  .  152 


CONTENTS.  XI 

PAET  II. 

THF  MANUFACTURE  OF  STARCH-SUGAR. 

SECTION  I. 
THE  CHEMISTRY  OF  STARCH-SUGAR. 

PAQB 

HISTORY,  LITERATURE,  AND  TERMINOLOGY 153 

Discoveries  of  Kirchhoff,  Foulcroy  and  others ;  origin  of  glucose 
manufacturing  at  time  of  Napoleon  I.  .  .  .  .  .153 

Great  importance  at  present  of  this  industry  in  Europe,  on  account 
of  the  want  of  molasses,  where  beet-sugar  is  manufactured  ;  seats 
of  this  industry  in  Europe  and  America  .  .  .  .  .154 

Grape-sugar,  starch-sugar,  potato-sugar,  uric-sugar,  dextrose,  gly- 
cose  or  glucose,  what  they  comprise  ;  names  used  in  France  ; 
sugar  wherein  found,  and  in  what  percentage  .  .  .  .155 

Grape-sugar,  what  quantities  found  in  various  kinds  of  fruit ;  physio- 
logical class  to  which  saccharine  compounds  belong  .  .  .156 

Formation,  chemical  composition  of  pure  starch,  and  its  transforma- 
tion into  glucose  or  starch-sugar ;  chemical  composition  of  starch- 
sugar,  cane-sugar,  and  grape-sugar  .  .  .  .  .  .157 

Saussure  on  the  decomposition  of  starch  ;  action  of  acids  on  sugar; 
explanation  of  the  transformation  of  cane-sugar  into  grape-sugar  .  158 

Physical  properties  ;  polarization  of  grape-  or  starch-sugar ;  process 
of  formation  ;  explanation  of  the  process  occurring  by  the  trans- 
formation of  starch  into  dextrine  and  glucose  .  .  .  .159 

The  transformation  of  starch  into  grape-sugar  and  dextrine,  accord- 
ing to  T.  Museums  .........  161 

Production  of  dextrine  and  starch-sugar  by  the  action  of  sulphuric  or 
muriatic  acid,  by  means  of  diastase,  or  diastase  and  yeast  com- 
bined ;  extracting  the  wood  fibre  from  wood ;  manufacture  of 
mucilaginous  sugar  by  means  of  malt  or  sulphuric  acid,  by  Anselm 
Payen 165 

Recent  improvements  in  the  transformation  of  starch  into  dextrine 
and  sugar,  by  T.  Museums  .  .  .  .  .  ...  .172 

On  the  effect  of  diastase  on  starch  under  various  conditions,  by  An- 
selm Payen  .  .  .  .  .  .  .  .  175 

Annotations  to  Payen's  essays,  by  G.  C.  Habich     .         .         .         .181 

On  transformation  of  starch  into  sugar  by  means  of  malt,  by  Dubrun- 
faut .  .  .184 

Deductions  from  the  different  opinions  set  forth  by  Payen,  Musculus, 
Dubrunfaut,  etc. 186 

CHEMICAL  PROPERTIES,  ACTION,  DECOMPOSITION 
Chemical  combinations    . 


xii  CONTEXTS. 


SECTION  II. 

THE  TECHNOLOGY  OF  STARCH-SUGAR,  THE  MANUFACTURE  OF 
STARCH-SUGAR. 

PAGE 

GENERAL  INTRODUCTION .         .     191 

Gallesizing  and  Petiotizing  ;  starch-sugar  must  always  be  considered 
a  substitute  for  crystallizing  sugar,  and  is  only  advantageous  when 
it  can  be  produced  more  cheaply  ;  the  transformation  of  starch  into 
sugar  .          .         .          .          .          .         .         .          .          .         .192 

Amidulin,  starch-gum,  and  starch-sugar  .         .         .         .         .          .193 

THE  MANUFACTURE  OF  GLUCOSE  AND  STARCH-SUGAR  FROM  STARCH     196 
Different  forms  in  which  sugar  produced  from  starch  appears  in  com- 
merce— starch  syrup,  imponderable  syrup  or  glucose,  granulated 
sugar,  common  solid  sugar,  refined  solid  starch  sugar    .          .          .197 

THE  MANUFACTURE  OF  GLUCOSE  SYRUP  AND  STARCH-SUGAR  FROM 

STARCH  BY  MEANS  OF  SULPHURIC  ACID 197 

The  process  of  boiling    .         .          .          .          .          .         .          .         .19^ 

Stirring  tub *     199 

Amount  of  water  and  sulphuric  acid  for  manufacture  of  glucose,  and 
for  solid  sugar  to  220  Ibs.  air-dry  starch  .  .  .  .  .201 

Boiling  by  steam 202 

Testing  the  liquid ;  the  removal  of  the  sulphuric  acid ; .  process  of 
neutralization  ..........  203 

Most  suitable  carbonate  of  lime  for  neutralization ;  testing  the  di- 
minution of  the  acidy  reaction  .  .  .  .  .  .  .  204 

Filtering  barrels ;  removing  the  sugar  liquor  from  the  sediment  by 
the  use  of  the  bag  filter;  Taylor's  bag  filter  .... 

Johnson's  filter  press      .     -     . 

The  process  of  evaporation      ........ 

Wet-air  pump         .......... 

Guild  &  Garrison's  vacuum  pump    ....... 

Vacuum  apparatus 

Vacuum  steam-jet  condenser 

Packing  and  transportation  of  the  liquid  syrup  or  glucose ;  difficulties 
overcome  by  introducing  this  article  of  commerce  in  the  form  of 
crude  or  refined  grape-sugar  ....... 

Classification  of  the  products  of  starch-syrup  and  starch-sugar  manu- 
facture— starch-syrup  or  glucose,  common  starch-sugar,  purified  or 
refined  starch-sugar,  granulated  starch-sugar  obtained  by  congela- 
tion , 


CONTENTS.  Xlll 

PAGE 

Chemical  composition  of  liquid  starch-syrup  or  glucose  and  common 

starch-sugar,  with  tables  of  analyses 224 

SPECIAL  DIRECTIONS  FOR  THE  MANUFACTURE  OF  STARCH-SUGAR    .  225 

Payen's  method  for  the  manufacture  of  starch-syrup  and  sugar         .  225 
Pay  en's  apparatus  for  his  method  of  manufacturing  glucose      .         .226 

Muubre's  method  for  the  manufacture  of  starch-syrup  and  sugar        .  230 

Maubr6's  apparatus  for  manufacture  of  glucose         ....  231 

Landmann's  method  of  manufacturing  starch-syrup  and  sugar  .         .  233 

Rossling  and  Reichardt's  apparatus  for  the  manufacture  of  glucose  .  234 

Anthon's  method  of  manufacturing  grape-sugar ;  boiling          .         .  236 

Neutralization 237 

Evaporation 238 

Pressure 239 

LafFerty's  centrifugal  machine 240 

Set  of  four  centrifugals  arranged  for  open  train,  with  vacuum  pans, 

H.  W.  Lafferty 241 

Remelting 242 

Utilization  of  the  pressed-out  sugar ;  aid  of  sulphurous  acid     .         .  243 

ANTHON'S   LATEST    IMPROVEMENTS   FOR  THE    MANUFACTURE   OF 

SMALLER  QUANTITIES;  HIS  PERFECTED  MACHINERY         .         .  244 
The  method  of  producing  352  to  444  Ibs.  of  glucose  within  twenty- 
four  hours ;  fitting  up  of  the  apparatus          .....  244 
Barrel  for  receiving  the  filtered  thin  juice  ;  manipulation           .         .  246 
The  production  of  capillair  syrup  and  sugar     .....  249 
Sugar  grating  machine  ;  granulated  starch-sugar      ....  252 
Hastening  the  bleaching  of  glucose  during  its  manufacture        .          .  253 
The  manufacture  of  grape-syrup  and  grape-sugar  from  grapes  and 
raisins          ...........  255 

THE  QUALITY  OF  STARCH-SUGAR;  DETERMINATION  AS  TO  IMPURI- 
TIES AND  ADULTERATIONS  OF  STARCH-SUGAR          .         .         .  256 
Anthon's  granulated  sugar       ........  256 

Dr.  Xewbauei-'s  analyses  of  grape-sugar  samples      ....  257 

Table  of  Dr.   Newbauer's  analyses;    E.    Schmid's  analyses,   Fred 

Mohr's  analyses 258 

Polarization;   Anthon's  method  of  testing  grape-sugar     .         .         .  259 
Table  for  ascertaining  the  purity  of  grape-sugar  according  to  the  me- 
thod of  Anthon ;  Gentele's  directions  for  the  qualitative  determina- 
tion of  grape-sugar       .         .         .         .         .         .         .         .         .261 

APPLICATION  OF  GLUCOSE  AND  GRAPE-SUGAR 263 

Improvement  of  wine  Gallizing  and  Petiotizing  ;  sugar  coloring        .  263 
Description  of  the  glucose  and  starch-sugar  manufactory  of  Noback 

Bros.  &  Fritze,  Prague,  Bohemia 264 


CONTENTS. 

SECTION  III. 

THE  MANUFACTURE  OF  SUGAR  COLOR  (COULEUR). 

PAGE 

Tincture  of  sugar ;  solution  of  burnt  sugar  or  caramel,  beer  couleur, 
rum  couleur,  whiskey  couleur,  etc 268 

Process  of  manufacturing  rum  couleur,  according  to  the  chemist 
Krotke,  of  Berlin  ...  .270 

Process  of  manufacturing  beer  couleur  according  to  the  same  authority     272 

Prof.  Otto's  receipt  for  the  manufacture  of  sugar  couleur          .         .     273 


PAKT  III. 

THE  MANUFACTURE  OF  DEXTRINE. 

SECTION  I. 
THE  CHEMISTRY  OF  DEXTRINE. 

History,  literature,  and  terminology ;  important  discovery  of  Bouillon 
La  Grange,  1810;  process  proposed  by  Dingier,  1820  .  .  .  275 

Results  of  the  experiments  of  Guibourt,  Doeberreiner,  Payen,  Loew- 
enhoek,  Vary,  Raspail,  and  Lassaigne  .  .  .  .  .276 

Experiments  of  Fritszche,  Guibourt,  Payen,  Fritsche,  Persoz,  Von 
Mohl,  Naegeli,  Biot,  and  Berzelius ;  origin  of  the  term  dextrine, 
also  called  dextrine-gum,  fruit-gum,  roasted  starch,  starch-gum, 
steamed-gum,  amidon-grille,  leiocome,  leiogomme,  gomme  d' Al- 
sace, gommeline,  etc.  .  .  .  .  .  .  .  .277 

SUBSTANCE  AND  NATURE .278 

ORIGIN  AND  FORMATION 279 

Amount  of  dextrine  in  grains  according  to  analytical  tests  ;  dextrine 
found  in  the  animal  kingdom  .  .  .  .  .  .  .279 

CHEMICAL  PROPERTIES        .........     280 

Experiments  of  Musculus  respecting  soluble  starch  and  globulus 
dextrine;  globulus  dextrine  . 282 

SECTION  II. 

THE  TECHNOLOGY  OF  DEXTRINE,  THE  MANUFACTURE  OF  DEXTRINE. 

THE  MANUFACTURE  OF  DEXTRINE  BY  ROASTING  OF  STARCH    .         .     284 
Dextrine  roasting  apparatus    .         .         .         .         .         .         .         .285 


CONTENTS.  XV 

PAGB 

Articles  produced  from  starch  by  this  apparatus       .         .         .         .287 

The  establishment  of  Proudfoot  &  Co.,  Manchester,  England   .         .     289 
Apparatus  of  Pay  en       .         .         .         .         .         .         .         .         .290 

Remarks  of  Prof.  Otto  of  Brunswick ;  Pochin  &  Wooley's  patented 
method  of  manufacturing  dextrine  ......  291 

THE  MANUFACTURE  OF  DEXTRINE  BY  APPLICATION  OF  ACIDS          .     292 

New  method  described  by  Fr.  Anthon 293 

Dextrine  cellular  apparatus     .         .         .         .         .         .         .         .     294 

THE  MANUFACTURE  OF  DEXTRINE  BY  MEANS  OF  DIASTASE       .         .  296 
Dextrine- sucree,  or  dextrine-sugar          .          .         .         .                  .297 

Payen's  apparatus  for  the  production  of  dextrine  and  diastase  .         .  298 

Recommendations  of  Payen  and  Persoz 299 

Experiments  for  producing  dextrine  from  Wood  by  Bracannot,  1820, 

and  subsequently  by  Vogel  and  Bertholet  and  Anthon           .         .  300 

Manufacture  of  chemically  pure  dextrine          .....  302 

Experiments  of  Payen  and  Barford          .         .         .         .         .         .  303 

QUALITY  OF  DEXTRINE  ;  TESTING  OF  DEXTRINE  AS  TO  ITS  CONTENTS 

OF  IMPURITIES  AND  ADULTERATIONS 304 

The  dextrine  of  commerce  ;  pure  dextrine       .....     304 

Dextrine  of  commerce  never  perfectly  pure ;  table  of  an  analyses  of 
commercial  dextrines ;  contents  of  starch-sugar  in  dextrine  proof 
of  the  difference  between  dextrine  and  gum-arabic  .  .  .  305 

Method  for  determining  the  amount  of  flour  and  other  adulterations 
in  dextrine  ..........  307 

Dyeing  experiments  for  determining  the  quality  of  dextrine     .         .     308 

APPLICATION  OF  DEXTRINE 309 

Substitute  for  Senegal  and  Arabic  gums ;  its  use  in  printing  cloths, 
Leveridge's  patent  for  preparing  artificial  gum  for  calico  printing  309 

Use  of  dextrine  by  paper-makers  for  gumming  envelopes,  and  postage 
and  revenue  stamps,  for  pastil  and  gouache  paintings,  for  the  manu- 
facture of  inks,  for  printing  rollers  and  bearers,  for  chain  dressing 
for  weavers,  for  lip  glue;  in  surgery  for  preparation  of  solid 
bandages,  in  pharmacy,  in  the  preparation  of  bread  and  cakes,  and 
the  brewing  of  beer  .  .  .  x  .  .  .  .  .  310 

Plan  for  the  establishment  of  a  potato-starch  and  dextrine  manufac- 
tory with  the  latest  improvements  .  .  .  .  .  .311 


XVI  CONTEXTS. 

APPENDIX. 

THE  METRIC  SYSTEM  OF  WEIGHTS  AND  MEASURES. 

PAGE 

We'ghts  and  measures  .         .         .         .         .         .         .         .         .         .319 

Tables  showing  the  relative  values  of  English  and  French  measures       .     321 
Hydrometers  and  Thermometers    .         .         .         .         .         .         .         .329 

Thermometers 331 

Centigrade  and  Fahrenheit 332 

INDEX  ....  .  335 


A 


OX    THE 


MANUFACTURE  OF  STARCH,  GLUCOSE, 
STARCH-SUGAR,  AND  DEXTRINE. 


SECTION  I. 

THE  CHEMISTRY  OF  STARCH. 

INTRODUCTORY. 

STARCH,  or  starch-flour,  was  known  to  the  ancient 
Egyptians  and  Greeks,  but  at  that  remote  age  it  was 
exclusively  manufactured  of  wheat.  The  starch  pro- 
duced by  the  inhabitants  of  the  island  of  Chios  was 
much  valued,  and  was  used  for  medicinal  purposes  as 
well  as  for  food.  According  to  Pliny,  we  are  indebted 
for  the  making  of  starch  from  wheat  to  the  inhabitants 
of  Chios.  But  the  production  and  application  of  starch 
from  potatoes  appears  to  be  an  invention  of  more  re- 
cent times,  and  dates  from  the  close  of  the  16th  and 
the  beginning  of  the  17th  century,  while  the  literature 
pertaining  to  this  branch  of  industry  commences  with 
the  year  1739 ;  since  which  time  many  treatises  on  this 
subject  have  made  their  appearance  in  the  various  lan- 
guages of  continental  Europe. 

APPEARANCE  AND  VALUE. 

Starch  is  not  only  one  of  the  most  extensively  dif- 
fused, but  also  one  of  the  most  useful  ingredients  con- 

2 


18  MANUFACTURE    OF    STARCH,    ETC. 

tained  in  plants.  It  is  important  on  account  of  its 
scientific  relations,  with  regard  to  the  vitality  of  plants 
and  their  chemical  action,  and  of  the  highest  practical 
interest  in  the  industrial  arts,  and  for  domestic  and 
agricultural  purposes.  Starch  appears  not  only  in  all 
the  different  species  of  plants,  but  it  is  found  in  all 
the  various  parts  of  the  same.  Starch  appears  in  the 
roots,  bulbs,  and  stalks,  in  the  trunks  (both  in  the 
wood  and  in  the  bark  of  trees),  as  also  in  the  leaves, 
blossoms,  fruits,  and  seeds  of  the  most  varied  spe- 
cies of  plants.  Many  plants  and  products  prepared 
from  plants,  which  serve  as  nutriment  for  man  and 
beast,  are  distinguished  on  account  of  their  large 
yield  of  starch,  as,  for  instance,  the  various  species 
of  grain,  such  as  corn,  wheat,  rice,  rye,  barley, 
maize,  etc. 

In  order  to  be  enabled  to  separate  the  starch  from 
the  plants  to  make  it  remunerative,  it  becomes  above 
all  necessary  to  be  able  to  gather  the  respective  vege- 
table substances  in  large  quantities,  and  such  of  a  rich 
yield,  that  the  separation  of  the  starch  ensues  with- 
out difficulty,  and  finally,  that  the  product  obtained 
possesses  withal  those  properties  whereby  it  becomes 
valuable  for  the  different  purposes.  It  occurs,  how- 
ever, frequently  that  starch  might  be  separated  inex- 
pensively and  in  large  quantities,  but  that  such  starch 
contains  such  properties  as  make  it  quite  useless 
for  any  practical  purposes.  Such  starch  is  frequently 
of  various  colors,  or  it  has  an  admixture  of  foreign  in- 
gredients, to  remove  which  would  entail  expense,  not 
worth  the  trouble,  and  hence  for  practical  purposes  it 
would  be  entirely  or  partly  useless. 

Among  the  products  from  the  vegetable  world, 
which  yield  commercial  starch,  we  name  the  following, 


INTRODUCTORY. 


19 


viz.,  potatoes,  wheat,  maize,  and  rice,  and  to  the  elu- 
cidation of  these  products  this  treatise  will  be  more 
prominently  devoted. 

The  value  or  percentage  of  starch  contained  in  these 
various  species  of  corn  and  grain — dried  in  an  atmo- 
sphere of  100°  C.  (212°  F.)— can  be  gleaned  from  the 
following  table: — 


According  to  Krocker's 
analysis. 

Mean  ratio. 

From 

To 

Wheat       . 
Rye    ... 

66.93 

60.o6 
77.74 
85.78 
70.50 
1270 

67.42 
61.26 

67.20 
60.90 
77.77 
8430 
76.50 
16.50 

Rice  ... 

Potatoes    . 
Potatoes  (air-dry) 

86.63 
83.50 
20.71 

As  the  percentage  of  the  product  of  starch  men- 
tioned above  is  given  as  it  appears  in  the  air-dry  state, 
it  will  be  necessary  also  to  include  here  the  quan- 
tity of  hygroscopic  water  contained  in  the  different 
species,  for  which  purpose  the  table  below  may  serve. 


Starch. 

Protein 
sub- 
stances. 

Fat, 

Ashy  in- 
gredients. 

Fibrin. 

Water. 

Wheat      . 
Rice 
Maize 
Potatoes 

633 
74.5 
645 
200 

14.4 

7.8 
9.9 

1.9 
0.2 

6.7 

1.7 
0.3 
1.4 

4.2 

3.4 
4.0 

14.5 
13.7 
13  5 
76  0 

FORMATION,  SUBSTANCE,  AND  NATURE  OF  STARCH. 

Starch,  according  to  the  opinion  of  the  scientific  men 
of  the  present  age— even  without  regard  to  its  organ- 
ized structure — is  merely  to  be  considered  as  a  product 
formed  by  the  vital  activity  of  plants,  and  hitherto 


20  MANUFACTURE    OF    STARCH,    ETC.     . 

chemistry  has  not  been  able  to  produce  a  body  which 
would  even  possess  the  chemical  properties  of  the 
same,  while  we  are  enabled  by  chemical  process  to 
produce  substances  which  approach  it — for  instance, 
gum  (dextrine),  starch-sugar,  glucose,  etc.  The  forma- 
tion of  starch  in  animalic  substances,  hitherto  proble- 
matical, we  will  not  consider  here,  although  some  have 
endeavored  to  prove  its  existence  in  the  spleen,  the 
liver,  and  the  kidneys  of  animals. 

The  formation  of  starch  pertains,  beyond  doubt,  to 
one  of  the  most  vital  actions  in  the  life  of  plants,  and 
it  is  most  probable  that  it  originates  from  the  gum- 
resin  or  mucilaginous  matter.  In  many  instances, 
starch  is  to  be  considered  as  the  final  product  in  the 
process  of  vegetable  life,  while  in  other  respects  it 
appears  manifestly  as  a  product  of  transition.  In  the 
latter  case  it  disappears  again  at  a  certain  period,  in 
order  to  serve  as  material  for  other  substances  (gum, 
sugar,  etc.),  or,  and  principally  perhaps,  to  be  used 
for  the  structure  of  the  cellular  tissue  in  the  form  of 
vegetable  fibre  (cellulose).  Thus  for  instance  unripe 
kernel  fruit  contains  large  quantities  of  starch,  which 
however  disappears  when  the  fruit  ripens.  It  is  a 
fact,  based  on  science,  that  starch  and  fibres  come 
near  in  their  chemical  properties,  and  this  will  become 
all  the  more  obvious  when  it  is  considered  that  they 
really  possess  the  same  chemical  constitution,  since 
the  cellulose  may  be  considered  as  being  starch  in  a 
more  cohesive  state. 

The  disappearance  of  the  starch  already  formed 
does  not  take  place  at  the  time  of  the  actual  germi- 
nation of  the  seeds  in  the  ground,  or  at  the  period 
of  the  malting  of  the  grain,  nor  does  it  happen  at  the 


INTRODUCTORY.  21 

time  of  the  sprouting  of  the  potatoes  at  their  place  of 
keeping,  etc.,  but  it  ensues  (especially  in  the  case  of 
potatoes)  in  consequence  of  their  containing  a  large 
quantity  of  water  at  the  beginning  of  germination, 
and  this  circumstance  furnishes  the  reason  for  the  fact 
that  the  amount  of  starch  in  potatoes  which  increases 
with  their  maturing  and  ripening,  gradually  decreases 
during  their  being  kept  in  store,  or  during  winter. 

It  has  been  asserted  that  the  want  of  light  tends  to 
increase  the  formation  of  starch,  but  this  opinion  we 
deem  fallacious,  since  those  parts  of  plants  which  are 
more  particularly  excluded  from  the  influences  of 
light,  do  not  contain  a  larger  amount  of  starch,  but 
as  is  well  known,  the  yield  in  starch  of  the  various 
species  of  grain  is  much  larger  than  that  of  the 
potato,  and  it  can  certainly  not  be  asserted  of  either 
grain  or  maize,  that  their  richer  yield  in  starch  is  to 
be  derived  from  the  consequence  of  want  of  light 
during  their  process  of  development. 

The  main  point  in  question  is  to  ascertain  the 
manner  of  the  formation  and  growth  of  the  starch 
granules.  For  the  correct  solution  of  this  difficult 
question  we  are  indebted  to  the  investigations  of 
Ncegeli,  who  has  furnished  the  proof  that  the  growth 
of  the  starch  granules  ensues  by  the  penetration  of 
starch  producing  liquid  hydrates  of  carbon.  They 
penetrate  from  without  into  the  interior  of  the  grain. 
The  substance  of  the  starch  granules  increases  in 
density  from  within  to  without,  while  the  quantity  of 
moisture  increases  from  without  to  within.  The  starch 
granules  consist  of  an  outer  denser  layer  having  but 
little  moisture,  followed  \\j  one  of  lesser  density,  but 
containing  more  water,  upon  this  follows  again  a  denser 


22  MANUFACTURE    OF    STARCH,    ETC. 

layer  of  smaller  amount  of  water,  etc.  etc.,  until  finally 
in  the  centre  a  soft,  more  water-containing  nucleus  is 
found.  The  botanist  SMeiden  was  the  first  who 
observed  that  the  inner  strata  of  starch  granules  gene- 
rally abound  more  in  water,  and  are  consequently 
more  gelatinous,  the  outer  layers  less  moist  and  are 
therefore  denser. 

Starch  consists  of  an  easily  soluble  mass,  the  "gran- 
ulose,"  and  an  insoluble  substance,  "  starch  cellulose." 
Both  these  substances  are  distributed  through  the 
entire  body  of  the  starch  grannies,  and  not  merely 
separated  and  deposited  in  the  various  layers  of  the 
grain.  Fibrin  (cellulose),  according  to  its  chemical 
nature,  is  an  ingredient  which  is  always  homogeneous, 
and  a  prominent  part  in  all  plants;  forming  in  the 
shape  of  cellular  tissues,  so  to  say,  the  skeleton  of  the 
plants.  Fibrin,  as  already  stated,  has  much  that  is 
similar  to  starch,  and  both  form,  when  exposed  to  the 
action  of  sulphuric  acid,  dextrine  and  sugar;  both 
are  transformed  by  the  application  of  caustic  alkalies 
and  nitric  acid  into  oxalic  acid ;  both  form  under  cer- 
tain conditions  explosives,  the  starch  xylodin,  the 
plant  fibre  gun-cotton  (pyroxilin). 

Starch  is  frequently  considered  as  that  substance 
(nutriment),  by  which  the  cellular  tissues  of  plants  are 
formed ;  and  many  physiologists  assert  that  the  fibre 
itself  can  be  retransformed  even  in  the  plant  into 
starch,  which  latter  opinion  is  nevertheless  dubious. 

Berzelius  distinguished  two  different  forms  of  fibrin 
in  plants  :  first,  that  which  is  found  in  wood  and  hard 
shells  and  seeds  (for  instance  in  the  coffee  bean)  ;  and 
secondly  as  cellular  skeletpn  of  the  softer  parts  of 
plants,  for  instance  that  in  beets,  and  various  other 
truck  vegetables ;  the  former  he  termed  Xylon  or 


INTRODUCTORY.  23 

strong   cellulose,  the  latter  Amylon,  that   is   tender 
(soft)  cellulose. 

PHYSICAL  PROPERTIES. 

Organization,  Structure,  Form  and  Size. — The  starch 
appears  as  deposited  in  the  tissues  of  plants,  when 
being  viewed  under  the  lens  of  a  microscope,  like 
rounded-off,  colorless,  transparent,  or  glassy  lustrous 
globules  of  various  sizes,  form  (shape),  and  aggrega- 
tion, partly  more  or  less  spherical,  and  again  more  of 
an  eliptical  shape  (lentil  formed),  i.  e.,  pressed  flat, 
disk-like,  and  occurring  either  in  single  (simple)  gran- 
ules or  bar-shaped,  adhering  or  stuck  together. 

Dry  starch,  especially  potato  starch,  appears  as  a 
white,  glossy,  in  the  sunlight  glittering,  powder,  some- 
what hard  of  touch  and  of  1.53  specific  gravity  (1.505 
at  19.7°  C.  =  67.5°  F.).  Moistened  starch  can  be 
formed  into  balls,  which  even  after  drying  adhere 
together,  and  do  not  break  up,  without  the  use  of  some 
force.  After  a  complete  extraction  by  cold  water, 
alcohol  or  ether,  it  loses  those  properties,  by  which 
it  may  be  turned  into  balls,  and  therefore  the  proper- 
ties cannot  be  ascribed  to  the  starch  itself,  but  to  the 
extractive  nature  of  the  ingredients  of  its  composition. 
Chemically  pure  starch  forms  a  tasteless,  odorless 
powder,  entirely  indissoluble  in  water,  alcohol,  and 
ether.  The  polarization  of  starch  is  of  great  interest, 
but  the  various  kinds  do  not  polarize  uniformly. 

Among  other  physical  properties  of  starch,  it  should 
be  finally  mentioned  that,  when  it  is  brought  in  contact 
with  aqueous  vegetable  decoctions,  also  with  wine, 
beer,  etc.,  it  will  discolor  the  same,  that  is,  it  will  ex- 
tract the  pigment  therefrom.  The  size  of  the  starch 


24  MANUFACTURE   OF   STARCH,    ETC. 

granules  varies  considerably,  not  only  among  the  va- 
rious kinds,  but  also  among  the  same  kind,  according 
to  the  age  and  the  advancement  in  the  growth  of 
the  granules,  as  well  as  with  regard  to  the  organization 
of  the  plant  from  which  they  originated. 

CHEMICAL  PROPERTIES. 

The  More  Immediate  Ingredients  of  StarcJi. — Starch, 
with  regard  to  its  chemical  nature,  belongs  to  chemi- 
cally "indifferent  substances,  i.  e.,  to  the  so-called 
hydrates  of  carbon,  or  to  that  group  of  organic  bodies 
which,  besides  carbon,  contain  hydrogen  and  oxygen 
in  such  proportions  that  they  could  form  water  when 
combined  with  each  other.  The  general  formula 
for  hydrates  of  carbon  is,  CxHnOn,  or  CX(H2(^),  or 
C,(H20)n. 

In  the  group  of  hydrates  of  carbon  we  count,  among 
others,  cellulose,  starch,  dextrine,  cane-sugar,  milk- 
sugar,  grape-sugar,  etc.  As  regards  its  elementary 
composition,  starch  in  a  perfectly  pure  and  dry  state 
is  composed  of— 

12  equivalents  of  carbon, 

10  "  hydrogen,  and 

10  "  oxygen, 

hence  the  formula  =  Ci2H10Oi0,  or,  according  to  modern 
style,  C6Hi0O.3,  and  corresponds,  therefore,  as  to  its 
composition,  with  that  of  fibrin  (cellulose)  and  dex- 
trine entirely. 

In  a  perfectly  air-dry  state,  starch  contains  18  per 
cent.,  or  four  equivalents  of  water,  of  which,  how- 
ever, two  equivalents  or  one-half  will  evaporate  in  a 
vacuum  over  concentrated  sulphuric  acid.  As  has 


INTRODUCTORY.  25 

already  been  stated,  the  various  layers,  of  which  every 
single  starch  granule  is  formed,  do  not  differ  chemi- 
cally, except  as  to  the  somewhat  larger  amount  of 
water  contained  in  those  of  the  inner  strata. 

Although  starch  contained  in  different  plants  is,  as 
to  its  chemical  relations,  entirely  identical,  yet,  con- 
sidered from  an  industrial  or  mercantile  point  of  view, 
it  essentially  differs.  In  its  perfectly  pure  state,  it 
is  designated  generally  as  odorless  and  tasteless; 
however,  potato  starch  has  always  a  peculiar  smell, 
which,  according  to  Pay  en,  originates  from  small  por- 
tions of  volatile  oil. 

Starch  never  appears  in  an  entirely  pure  state.  It 
always  contains — although  mostly  in  but  very  minute 
portions — some  natural  impurities,  such  as  chlorophyll, 
solid  and  volatile  oils,  and  wax,  besides  the  incidental 
impurities  while  being  manufactured,  such  as  fibrous 
matter,  earths  and  salts,  imparted  as  impurities  by 
water  used  •  for  the  washing  of  the  same,  albumen, 
alum,  etc.,  which  latter,  as  to  its  ratio  of  percentage 
contained  in  commercial  starch,  sometimes  amounts  to 
a  great  deal. 

The  Relations  of  Starch  to  Warmth,  Water,  Acids, 
Bases,  Alkalies,  and  Diastase. — It  has  been  known 
for  a  long  time  that  starch  when  roasted — like  gum — 
becomes  soluble  in  water,  but  the  products  ensuing 
by  this  transformation  were  not  known.  Only  at  a 
later  period  was  it  proved  that  starch,  by  the  process 
of  roasting,  is  transformed  into  dextrine,  or  starch- 
gum,  which  process  can  be  greatly  accelerated  by  the 
addition  of  small  quantities  of  acids,  especially  muri- 
atic, nitric,  or  sulphuric  acid,  whereby  also  various 
quantities  of  starch-  or  grape-sugar  (glucose)  are 
formed. 


26  MANUFACTURE   OF    STARCH,    ETC. 

It  is  self-evident  that  higher  or  lower  tempera- 
tures acting  on  the  starch  will  bring  divers  products. 
Thus  perfectly  dry  starch  can  bear  a  temperature  of 
160°  C.  (320°  F.)  without  a  material  change,  but  when 
this  heat  is  increased  to  200°  C.  (392°  F.)  the  starch 
will  turn  into  brownish-yellow,  and  thereby  change 
into  dextrine.  Moist  starch-flour  (containing  about 
10  to  20  per  cent,  of  water)  will,  in  a  closed  vessel, 
under  the  simultaneous  influence  of  steam  and  in- 
creased pressure,  change  readily  at  a  temperature  of 
160°  C.  (320°  F.)  into  dextrine. 

The  action  of  starch  at  the  freezing  point  is  highly 
interesting.  Vogel  observed  that  starch,  ^hen  boiled 
in  water,  and  the  paste  thus  obtained  exposed  to 
freezing,  will,  when  thawing,  not  retain  its  former  uni- 
form condition.  But  a  translucent  aqueous  liquid  will 
then  separate,  while  on  the  bottom  of  the  vessel  an 
elastic  substance  will  remain,  which  is  no  longer  suit- 

/  c!3 

able  for  pasting.  This  mass  furnishes,  when  strained  oif 
through  linen,  a  corresponding  quantity  of  clear  water 
(in  which  but  ver}7  little  starchy  substance  appears 
dissolved),  and  also  a  nice  white  cake,  which  latter, 
after  a  short  time,  becomes  so  dry  that  it  can  be  grated 
into  a  fine  white  powder,  which,  when  treated  in  hot 
water,  again  swells  up,  but  without  forming  the  same 
cohesive  pasty  mass  as  before. 

Starch  treated  in  this  manner  may  be  applied  in  the 
process  of  manufacturing  the  finest  qualities  of  paper, 
particularly  of  entirely  translucent  parchment  paper, 
also  for  preparing  perfectly  pure  colodion,  as  well  as 
for  other  purposes  of  the  arts.  The  so-called  pearly 
lustre  for  the  use  of  bookbinders,  is  prepared  in  this 
manner. 


INTRODUCTORY.  27 

Relations  of  Starch  to  Water. — To  cold  water  starch 
is  entirely  indifferent,  and  settles  in  it  when  by  dili- 
gent stirring  it  has  become  divided  into  small  parts, 
and  after  the  liquid  is  thus  allowed  again  to  settle  on 
the  bottom  it  will  show  no  perceptible  change  either 
in  the  quantity  or  the  quality.  If  starch  is  heated  in 
from  twelve  to  fifteen  times  its  quantity  of  water 
to  58°  C.  (136.4°  F.),  the 'starch  granules  begin  to 
swell,  and  the  higher  the  temperature  is  increased,  the 
larger  the  quantity  of  the  granules  will  be,  which  show 
the  same  symptoms.  Gradually  more  starch  granules 
will  expand,  and  this  will  ensue  in  the  case  of  some 
kinds  of  starch  already  at  55°  to  87.5°  C.  (131°  to 
189.5°  F.).  They  will,  moreover,  expand  in  such  a 
manner  that  the  single  layers  will  burst  open,  and  by 
a  copious  absorption  of  water  by  the  spongy  mass,  the 
so-called  paste  formation  will  ensue.  Paste,  which 
has  been  formed  in  a  temperature  below  100°  C.  (212° 
F.)  contains  no  starch  in  solution,  but  is  merely  to  be 
regarded  as  a  product  of  the  swelling  of  its  separate 
granules,  which  in  this  burst  or  cracked  condition — 
as  it  were  a  sponge — are  able  to  absorb  an  extraordi- 
nary amount  of  water.  The  absorbed  water  can,  how- 
ever, be  again  drained  off,  by  repeatedly  placing  it  on 
porous  filters  (slabs  of  clay,  tissue  paper,  etc.),  when 
after  drying  a  horny  substance  will  remain,  which  after 
pulverizing  is  again  ready  to  form  a  paste. 

The  ability  to  form  paste,  or  the  stiffening  power 
inherent  in  the  various  starches,  differs  greatly,  and 
this  qualification  is  practically  of  great  importance, 
since  starch  is  applied  above  all  for  the  stiffening  of 
linen  ("starching"),  for  preparing  bookbinders'  paste, 
and  for  the  finishing  of  the  textiles.  It  is,  therefore, 
of  great  importance  to  know  the  different  temperatures 


28 


MANUFACTURE    OF    STARCH,    ETC. 


at  which  respectively  the  swelling  and  the  paste  for- 
mation of  the  various  kinds  of  starch  ensues,  and  the 
following  table  may  serve  as  a  guide: — 


Perceptible 
•  '    swelling. 

Paste  formation 
begins. 

Paste  formation 
becomes  perfect. 

Degrees  according  to 

Celsius. 

Fahr. 

Celsius. 

Fahr. 

Celsius. 

Fahr. 

Rice  starch  ..... 
Potato  starch       .... 
Maize  starch        .... 
Wheat  starch       .         .        .         . 

53.75 
46.25 
50 
50 

128.8 
115.2 
122 
122 

58.75 

58.75 
55 
65 

137.8 
137.8 
131 
149 

61.25 
62.5 
62.5 
67.5 

142.3 

144.5 
144.5 
153.5 

In  order  to  make  a  good  starch  paste,  in  an  expedi- 
tious way,  the  starch  to  be  used  for  the  purpose  is 
mixed  with  some  water  until  it  becomes  a  thick  milky 
substance,  and  then  pouring  the  same  in  the  shape  of 
a  thin  stream  into  a  corresponding  quantity  of  boiling 
water,  which  is  to  be  kept  in  motion  by  constant  stir- 
ring. This  manipulation  may  also  be  reversed,  and  the 
same  result  attained  thus  :  by  diligently  stirring  the 
boiling  water,  while  pouring  the  same  gradually  into 
the  stiff  and  cold  mixed  starch-milk.  In  both  cases 
the  process  of  paste  formation  will  be  the  same,  but  by 
applying  dry  starch  this  will  not  be  the  case.  Starch 
paste  decomposes  when  exposed  to  the  air,  even  in  an 
ordinary  temperature,  and  is,  according  to  the  investi- 
gations of  Saussure,  transformed  into  sugar,  gum,  and 
other  products.  In  the  presence  of  gluten  this  decom- 
position takes  place  after  the  lapse  of  but  a  very  few 
hours. 

^Relation  of  Starch  to  Acids. — Not  less  remarkable, 
and  in  a  technical  chemical  respect  even  still  more  im- 
portant, is  the  relation  of  starch  to  the  various  acids. 
In  general  acids,  greatly  diluted,  transform  starch  into 


INTRODUCTORY.  29 

dextrine  (gum)  and  starch — or  grape-sugar  (glucose)  ; 
while  concentrated  acids — especially  when  applied  for 
an  extended  time — into  diverse  organic  acids,  as  formic 
acid,  glucinic  acid,  apo-glucinic  acid,  etc.,  and  various 
other  products  of  decomposition. 

The  relations  of  starch  to  oxalic  acid,  tartaric  acid, 
and  tannic  acid,  have  also  for  many  years  been  a  sub- 
ject of  investigation,  and  especially  Anihon  has  made 
a  series  of  experiments  respecting  the  relations  which 
starch  bears  to  silicic  acid,  from  which  we  learn  that 
starch,  during  a  continued  heating  with  this  acid,  will 
be  but  little  changed,  and  a  real  formation  of  dextrine 
will  not  thereby  occur.  In  a  general  way,  we  may 
therefore  assert,  that  all  organic  and  inorganic  acids 
in  diluted  form,  excepting  only  phosphoric,  silicic,  and 
acetic  acids,  will  transform  starch  into  dextrine  and 
sugar;  while  at  the  same  time  the  influence  of  acids 
on  starch,  according  to  their  nature,  their  degree  of 
concentration,  and  according  to  their  action  in  an  ordi- 
nary or  a  higher  temperature,  will  be  varying. 

Relation  of  Starch  to  Diastase,  Gluten,  Animalic 
Liquids,  etc. — Exactly  in  the  same  manner  as  diluted 
acids  act,  in  a  higher  temperature,  on  starch,  so  also 
some  other  organic  substances  act  on  the  same,  thus 
especially  diastase,  mouth  saliva,  abdominal  saliva, 
gastric  juice,  blood  serum,  gall,  etc.,  by  transforming 
the  same  into  dextrine  and  grape-  or  starch-sugar 
(glucose). 

Diastase,  an  azotic  substance,  soluble  in  water, 
and  itself  in  a  state  of  continual  decomposition,  and 
hence  of  a  changeable  composition,  is  formed  from  the 
protein  substances  of  grain  during  their  process  of 
germination.  It  forms  not  only  in  malt,  but  more- 
over in  all  germinating  seeds.  The  working  of  dias- 


30  MANUFACTURE   OF   STARCH,    ETC. 

tase  results  best  in  a  temperature  of  from  60°  to 
70°  C.  (140°  to  158°  F.).  After  it  •  reaches  75°  C. 
(167°  F.)  it  decreases,  and  finally  ceases  entirely.  Of 
this  action  of  diastase  good  use  is  made  in  distil- 
leries and  breweries,  while  the  action  of  the  saliva  of 
the  mouth  and  abdomen  produces  the  digestion  of  the 
starch  in  the  animal  system. 

Relation  of  Starch  to  Bases  and  Alkalies. — The  ac- 
tion of  starch  on  alkalies  is  very  singular.  The  latter 
possess,  even  in  a  cold  and  diluted  condition,  similar 
to  the  action  of  boiling  water,  the  power  to  transform 
the  amylum  into  a  semi  translucent  jelly,  like  a  paste, 
while  they  more  or  less  destroy  the  strata  of  the  starch 
granules,  and  cause  thereby  an  extraordinarily  strong 
swelling  of  the  same.  If  starch  is  brought  in  contact 
with  a  solution  containing  one  and  a  half  to  two  per 
cent,  caustic  potash  or  caustic  soda,  it  will  swell  up 
seventy-five  fold  of  its  original  volume. 

'This  ability  of  absorbing  alkaline  liquids  possessed 
by  the  starch  granules,  can  be  greatly  increased  by 
completely  drying  out  the  starch. 

Ammonia  (volatile  alkali)  causes  no  pasty  forma- 
tion. If  to  a  solution  of  salts  of  ammonia  a  small  quan- 
tity of  starch  is  added,  and  also  a  few  drops  of  liquid 
soda-lye,  the  starch  will  remain  unchanged  until  the 
entire  quantity  of  the  ammonia  salt  becomes  decom- 
posed, but  the  single  starch  granules  swell  visibly  as 
soon  as  a  small  surplus  of  soda  is  present.  The  alka- 
line solutions  of  starch  can  be  precipitated  by  means 
of  blue  vitriol  (sulphate  of  copper)  in  the  form  of  a 
blue  substance,  which  being  soluble  in  pure  water  can 
be  boiled  without  changing  its  color  to  black,  where- 
from  it  follows  that  this  precipitate  consists  of  a  com- 
position of  starch  and  copper,  but  it  is  not  hydrate  oxi- 


INTRODUCTORY.  31 

dulated  copper,  which  latter,  as  is  well  known,  loses 
its  hydratic  parts  by  boiling,  and  then  turns  to  a 
black  color.  This  action  of  starch  on  copper  solutions 
makes  it  possible  accurately  to  determine  the  quantity 
of  starch-  or  grape-sugar  contained  in  any  starch,  since 
this  action  of  the  starch  precipitates  the  copper  in  the 
form  of  hydrate  of  protoxide  of  copper. 

Although  amylum  (starch)  is  generally  considered 
as  a  neutral  or  indifferent  chemical  body,  it  possesses, 
nevertheless,  the  property  to  combine  under  certain 
conditions  with  several  bases,  as  barium,  lime,  and 
protoxide  of  lead. 

delations  of  Starch  to  Iodine,  Bromine,  and  Chlorine. 
— The  relation  of  starch  to  iodine  is  very  charac- 
teristic. Messieurs  Colin  and  Gauthier  made  the 
important  discovery,  in  1812,  that  iodine  with  starch — 
just  according  to  quantity  and  concentration  of  the 
solution  of  the  iodine  applied — will  cause  a  compound 
of  a  carmine-red,  violet,  or  transparent  (also  non-trans- 
parent) dark  blue  (with  large  quantities  of  starch), 
almost  black  colors,  which  is  called  iodine  starch. 
Thus,  iodine  may  be  applied  as  a  very  sensitive  test 
for  starch  (and  the  reverse).  Particularly  suitable 
for  this  purpose  are  the  solutions  of  iodine  in  water, 
alcohol,  or  an  aqueous  solution  of  iodide  of  potassium. 
The  peculiar  action  of  iodine  in  coloring  starch  red, 
violet,  or  blue,  does  not  merely  bear  upon  certain 
parts  of  the  starch  granules,  but  upon  their  entire 
substance,  and  is  so  extraordinarily  intense  that  in 
consequence  thereof  the  reaction  may  be  applied,  not 
merely  for  discerning  the  iodine,  but  also  the  starch 
itself;  and  this  can  be  done  with  great  reliance  in  all 
6ases,  even  when  these  substances  are  contained  in  any 
compound  in  but  very  minute  quantities.  A  starch 


32  MANUFACTURE    OF    STAKCH,    ETC. 

paste,  holding  iodide  of  potassium  of  but  0.0000025  to 
0.0000033  parts,  will  yet  turn  perceptibly  blue,  when 
for  the  purpose  of  disengaging  the  iodine  it  is  mixed 
with  common  sulphuric  acid  containing  some  nitric 
acid.  The  various  results  of  the  test  on  starch,  dex- 
trine, and  sugar  with  iodine  furnish  a  reliable  method 
of  accurately  pursuing  the  transformation  of  starch 
by  the  action  of  diluted  acids,  diastase,  etc.,  into  dex- 
trine and  glucose. 

Bromine  colors  starch  intensely  yellow,  while  chlo- 
rine^ on  the  other  hand,  bleaches  it. 

Fermentation  and  Decay. — Starch  is  not  fermenta- 
ble, and  the  opinion  of  those  who  deem  it  fermentable 
must  be  pronounced  as  decidedly  erroneous.  When 
even  common  sugar  (cane-sugar),  so  easily  soluble  in 
water,  cannot  ferment  without  passing  first  through 
the  condition  of  starch-  or  grape-sugar  (glucose),  how 
could  such  be  the  case  with  a  substance  like  starch, 
wrhich  is  not  soluble  in  cold  water? 

On  the  other  hand,  starch,  like  all  other  organic 
substances,  is  subject  to  putrefaction,  that  is,  decay, 
although  in  a  lesser  degree  than  various  other  matters. 
It  becomes,  when  somewhat  moistened,  especially  in 
stagnated  air,  easily  musty,  which,  doubtless,  must  be 
looked  upon  as  the  first  stage  of  decay.  In  general,  how- 
ever, it  withstands  this  tendency  with  greater  energy 
than  most  other  vegetable  substances,  especially  more 
so  than  the  indifferent  gum  of  plants,  which  is  solu- 
ble in  water,  or  the  scum  of  sugar,  and  other  vegetable 
substances,  etc.  But  starch  does  very  easily  and 
quickly  putrefy  when  it  is  previously  freed  of  its 
organic  structure,  and  when  it  has  been  transformed 
into  a  paste  or  solution.  This  subject  of  decomposition 
has  already  been  the  particular  study  of  Saussure, 


INTRODUCTORY.  33 

whose  reports  on  this  subject  are  even  to  this  day  of 
scientific  and  practical  interest.  Saussure  proved  that 
starch  paste,  when  exposed  to  the  air,  in  consequence 
of  a  milk  sugar  formation,  turns  sour;  and  that  with 
the  co-operation  of  gluten  and  similar  substances  it 
forms  butyric  acid,  since  a  part  of  the  starch  passes 
through  the  process  of  butyric  acid  fermentation. 
During  the  process  of  putrefaction  a  considerable 
quantity  of  glucose  is  also  formed. 


34  MANUFACTURE    OF    STARCH,    ETC. 


SECTION    II. 

THE  TECHNOLOGY  OF  STARCH.     THE   MANUFACTURE 

OF  STARCH. 

GENERAL  INTRODUCTION. 

FOR  the  manufacture  of  starch — without  regard  to 
what  kind  of  raw  material  —  it  becomes  above  all 
necessary  to  make  loose  that  part  of  the  plant  which 
surrounds  the  starchy  matter.  This  is  done  by 
loosening  the  cellular  tissues,  by  disaggregating  the 
same,  so  as  to  make  it  possible  to  separate  the  starch 
granules,  which  are  thus  laid  bare,  by  simply  washing 
them  out  with  water  (removing  the  dross),  and  in  this 
way  breaking  them  off  as  thoroughly  as  is  possible  from 
all  the  other  vegetable  substances.  Therefrom  it  fol- 
lows, that  from  the  theoretical  point  of  view  the  manu- 
facturing of  starch  still  depends  on  naught  else  but  a 
mechanical  operation.  In  the  practical  production  of 
this  article,  nevertheless,  some  chemical  phenomena 
present  themselves — this  is  particularly  the  case  in  the 
manufacture  of  starch  from  grain  and  especially  wheat 
— which  are  caused  by  fermentation,  putrefaction,  and 
other  transformations.  Moreover,  the  process  of  loos- 
ening and  separating  the  tissues — especially  in  the 
manufacture  of  starch  from  rice  and  maize — is  aided 
by  such  chemical  means  as  are  best  calculated  to 
dissolve  those  substances  which  give  to  the  cellular 
tissues  their  power  of  cohesion.  The  vegetable  sub- 


THE    TECHNOLOGY    OF    STARCH.  35 

stance,  removed  either  by  mechanical  power  alone,  or 
by  the  process  of  fermentation  and  other  solving 
agents,  is  thereupon  freed  from  the  starch.  This  can 
also  be  accomplished  by  kneading,  permitting  the 
fecula  to  settle  in  the  water,  and  after  washing  it  dry- 
ing it  out. 

We  have  previously  said  that  thus  far  no  plant  is 
known  which  does  not  contain,  during  certain  periods 
of  its  growth,  some  larger  or  smaller  quantity  of 
starch.  And  yet,  despite  all  this,  the  number  of  those 
plants  which  yield  sufficient  starch  for  purposes  of 
manufacture  in  quantities,  is  proportionately  but 
small,  and  is  limited  both  in  Europe  and  America 
chiefly  to  potatoes,  wheat,  rice,  and  corn  (maize). 
For  the  manufacture  of  starch  on  a  larger  scale,  those 
vegetable  substances  only  can  be  used  which  can  be 
gathered  in  large  quantities,  and  which,  furthermore, 
permit  of  the  process  of  separating  the  starch  without 
difficulty,  and  of  finally  furnishing  a  product  whose 
properties  render  it  suitable  for  the  different  practical 
purposes.  All  bulbs  and  roots  which  contain  an 
abundant  amount  of  starch  have  a  soft  and  tender 
tissue,  and  permit  the  separating  of  the  starch  without 
difficulty;  while  the  obtaining  of  starch  from  seeds 
and  fruits,  on  the  other  hand,  is  frequently  more  diffi- 
cult, on  account  of  the  denser  tissues  and  the  trouble 
of  removing  the  -covering  or  opening  the  tissues. 
Larger  quantities  of  gluten  in  seeds  make  it  often 
very  difficult  to  separate  the  starch  from  them,  or  cause 
it  to  be  so  expensive  that  a  separation  of  the  starch 
would  not  be  remunerative. 

In  the  United  States  starch  is  almost  exclusively 
manufactured  from  potatoes,  wheat,  maize,  and  rice. 
Inasmuch  as  potato  starch  is  cheaper  to  manufac- 


36  MANUFACTURE    OF    STARCH,    ETC. 

tnre  than  that  made  of  wheat  and  maize,  the  last 
two  are  only  applied  for  those  purposes  for  which 
the  former  is  really  not  advantageous.  For  the  finish- 
ing of  cotton  and  linen  textiles,  and  for  starching 
(stiffening)  cloth,  wheat  starch  is  better  suited  than 
potato  starch,  since  the  paste  made  of  the  latter  is  too 
translucent;  for  paper-hanger's  paste,  and  for  the  use 
of  bookbinders,  etc.,  wheat  starch  also  serves  best,  be- 
cause it  furnishes  a  better  sticking  paste  than  potato 
starch.  For  the  sizing  of  cotton  and  paper,  for  the 
manufacture  of  starch-gum,  starch-syrup,  and  starch- 
sugar,  potato  starch  may  be  applied,  and  for  these 
purposes  it  is  manufactured. 

The  yield  of  the  article  from  a  starch-containing 
substance,  all  other  things  being  equal,  is  greater, 
where  less  cellular  tissues  of  the  substance  remain 
closed  during  the  process  of  working  them,  since  no 
starch  granules  can  be  brought  forth  from  the  un- 
opened cells.  If  means  of  loosening  or  freeing  such 
granules  from  the  cells  were  known,  which  would  not 
injure  the  starch  granules,  we  would  be  enabled  to 
extract  from  every  vegetable  substance  the  entire 
contents  of  starch. 

The  primary  condition  for  rationally  establishing 
a  starch  manufactory  is  beyond  controversy  the  possi- 
bility of  a  good  location  so  as  to  have  easy  means  of 
furnishing  the  raw  material.  Besides  this  first  and 
most  important  requisite,  the  following  should  be  like- 
wise observed  : — 

1.  Easy  access  to  a  sufficient  supply  of  clear  water, 
with  drainage  for  the  running  off  of  the  water  used  for 
washing. 

2.  That  good  turnpikes  and  highways,  and  a  rail- 


THE    TECHNOLOGY    OF    STARCH.  37 

road  or  a  navigable  river  are  adjacent  to  the  establish- 
ment, and  thus  the  transport  and  traffic  made  easy. 

3.  That  the  necessary  fuel  (wood  and  coal)  can  be 
obtained  at  reasonable  rates. 

Of  great  influence  upon  the  exterior  appearance  of 
the  starch  is  the  condition  of  the  water,  as  regards  its 
purity  and  colorless  condition.  If  the  water  is  muddy, 
the  starch  will  settle  with  impure  substances,  and  im- 
part to  the  same  a  yellowish  color ;  this  also  happens 
if  the  water  is  not  entirely  colorless,  whereas  a  certain 
portion  of  the  pigment  thereof  dries  within  the  starch 
and  thus  reduces  its  whiteness. 

Water  of  a  brownish  color,  such  as  is  often  found  in 
marshy  or  moorish  ground,  may,  if  it  is  otherwise  clear, 
be  applied  for  the  first  washings  of  the  starch  flour, 
but  for  the  final  precipitation  it  must  be  absolutely 
colorless,  which  may  be  secured  by  mixing  it  with 
some  sulphuric  acid  or  a  solution  of  hypermanganate 
of  potassium.  Since,  as  has  just  been  stated,  the  last 
washing  only  requires  perfectly  colorless  water  — 
whose  quantity  is  not  large — the  cost  pertaining  to 
this  mode  of  purifying  is  but  very  small,  and  repays 
by  the  higher  price  obtainable  for  entirely  whitt 
starch,  more  than  double.  Some  mountain  waters  too 
— especially  when  the}7  hold  in  solution  carbonate 
of  lime — are  also  injurious  to  the  nice  appearance 
of  starch,  since  the  carbonate  of  lime  and  with  it  some 
coloring  matter  precipitates  and  discolors  the  starch. 
Such  a  water  is  best  treated  by  adding  sufficient  muri- 
atic acid,  in  order  to  neutralize  the  carbonate  of  lime 
t  lie  re  by.  In  most  of  such  cases  (30  grammes  (1.5  ozs.) 
commercial  muriatic  acid  are  ample  for  every  hecto- 
litre (2.8  bush's)  of  water.  This  can,  as  is  obvious, 
be  accomplished  with  very  little  expense.  Under  any 


38  MANUFACTURE    OF    STARCH,    ETC. 

circumstances  it  would  be  best,  should  the  lime  be  un- 
avoidable, to  have  it  in  the  form  of  chloride  of  calcium 
and  not  as  carbonate  of  lime. 


THE  MANUFACTURE  OF  POTATO  STARCH. 

In  the  first  place  we  will  turn  our  attention  to  the 
manufacture  of  potato  starch,  not  alone  on  account  of 
its  general  importance,  but  for  the  reason  that  it 
chiefly  forms  an  agricultural  occupation,  i.  e.  that  it 
may  be  combined  profitably  with  farming  and  is  carried 
on  extensively  in  this  way,  while  the  production  of 
other  important  species  of  starch,  such  as  wheat,  rice, 
and  maize  starch,  forms  each  a  separate  branch  of  indus- 
try, and  is  generally  carried  on  on  a  larger  scale.  This 
is  explained  from  the  fact  that  the  potato,  on  account 
of  its  large  contents  of  water,  contains  but  from  one- 
fourth  to  one-sixth  of  the  amount  of  starch  derived 
from  wheat,  maize,  or  rice,  and  hence  does  not  permit 
of  such  extended  transportation  from  a  distance,  and 
moreover  does  not  admit  of  such  long  storage  as  the 
various  species  of  corn.  The  process  of  making  potato 
starch  is  a  simple  one,  and  frequently  the  housewife  of 
a  farmer  makes  a  very  good  article  by  merely  using  a 
hand  grater  and  a  sieve. 

The  obtaining  of  potato  starch  requires  such  ma- 
nipulation that  the  cellular  tissues  of  the  potatoes, 
which  simply  envelop  the  starch  granules  and  more- 
over net-like,  are  to  be  dismembered  by  mechanical 
contrivances,  whereby  the  starch  granules  are  laid 
bare,  and  it  becomes  thus  possible  to  separate  these 
from  the  coarser,  flaky,  greatly  swelled  fibres,  by  the 
simple  means  of  sifting. 

One  of  the  greatest  difficulties  attending  the  manu- 


THE  TECHNOLOGY  OF  STARCH.          39 

facture  of  starch  from  potatoes,  is  the  transformation 
of  the  potato  into  the  most  possible  uniform  pulp  with- 
out carrying  on  the  process  of  bruising,  and  cutting 
up  the  cellular  substance  too  far,  which  is  unprofitable 
in  several  respects.  In  the  first  place,  it  should  be  con- 
sidered, that  thereby  too  much  fibrin  is  ground  so 
finely,  that  it  also  passes  through  the  sieves,  and  thus 
lessens  the  yield  of  the  first  quality  article;  and  second- 
ly, because,  by  a  too  extended  and  energetic  mechanical 
use  of  the  grater,  the  covers  wliich  envelop  the  starch 
granules  will  be  so  affected  that  the  value  of  the  arti- 
cle for  many  purposes  will  be  injured. 

THE  RAW  MATERIAL. 

The  potato  (Solanum  tuberosum  or  Solatium  esculen- 
tum  ;  English,  tuberous  potato  ;  French,  pomme  de  terre  ; 
German,  Kartoffel)  is  undoubtedly  one  of  the  most  im- 
portant and  useful  plants  arising  out  of  our  agricultural 
pursuits.  According  to  the  richness  of  the  soil  in  which 
potatoes  are  planted,  and  to  more  or  less  favorable 
weather,  the  yield  of  potatoes  is  regulated,  and  on 
these  circumstances  also  depends  the  quantity  of  starch 
contained  therein.  The  potatoes  contain  in  their 
cells  only  liquid  matter  (sap)  and  starch  granules. 
The  juice  or  sap  is  essentially  an  aqueous  solution 
composed  of  albumen,  gum,  and  diverse  salts.  The 
amount  of  starch  in  the  potato  is  very  fluctuating, 
and  may  rise  above  25  per  cent.,  but  may  also  fall 
below  15  per  cent.  The  substance  of  which  the 
textures  of  the  cells  are  composed  is  the  cellular  tissue 
of  plants  (cellulose)  ;  but  the  cellular  substance  of  the 
exterior  layer,  the  skin,  is  a  corky  substance  distin- 
guished by  its  imperviousness  to  water. 


TH* 


40  MANUFACTURE    OF   STARCH,    ETC. 

The  average  chemical  composition  of  good  potatoes 
can  be  expressed  in  percentage,  as  follows: — 

Starch         

Epidermis,  cellulose,  pectine,  pigment 
Albumen  and  other  azotics        ... 

Fat     .  

Sugar,  resin,  and  volatile  oil     ..... 

Salt  and  ashy  ingredients 

Water 

100.00 

The  many  analyses  have  proved  that  the  starch 
contents  vary  greatly,  not  only  in  the  different  species 
of  the  potatoes,  but  are  even  not  always  alike  in  the 
same  species.  They  vary  according  to  the  state  of  the 
soil  they  are  planted  in,  and  the  influences  of  the  pre- 
vailing weather  and  climate  during  their  growth;  and 
in  no  less  degree  also  on  the  fertilizer  used  for  making 
the  soil  richer. 

The  suitable  storing  (housing)  of  potatoes  is  for 
the  manufacturer  of  starch  of  the  greatest  importance, 
so  that  the  potatoes  are  thereby  protected  against'  the 
rot,  freezing,  and  germinating  (sprouting) — a  calamity 
which  not  only  influences  the  quality,  but  also  the 
yield  of  starch,  yea,  under  certain  conditions  will 
render  the  potato  entirely  unfit  for  the  production  of 
starch. 

By  storing  potatoes  in  well-constructed  bins,  silos, 
or  cellars  which  admit  no  frost,  their  contents  of  starch 
can  be  entirely  preserved,  whereas  frost  and  sprouting, 
as  well  as  the  rot,  will  materially  lessen  their  value 
for  technical  purposes. 

Determining  the  Amount  of  Starch  in  Potatoes. — The 
knowledge  of  the  amount  of  starch  contained  in  the 
potato  is  of  vital  importance  to  the  manufacturer  of 
starch.  This  amount  of  starch  can  only  be  judged 


THE  TECHNOLOGY  OF  STARCH.         41 

aproximately  and  empirically  from  the  condition  which 
the  potato  attains  after  boiling.  The  drier  (mealy), 
and,  so  to  say,  the  more  "crystalline"*  shining,  it  in 
that  state  appears,  the  richer  it  will  be  in  starch; 
while,  conversely,  a  lesser  content  of  starch  may  be 
connte4  on,  the  more  watery  and  transparent  the  boiled 
substance  appears.  It  must,  however,  be  understood 
that  such  a  method  is  not  at  all  suited  for  even  an 
approximate  determination  of  the  starch  value  of  pota- 
toes. But  quite  different  are  the  relations  of  the 
amount  of  starch  in  the  potatoes  toward  the  specific 
gravity,  which  depends  on  the  principle  that  all  solid 
ingredients  (dry  substance)  of  the  same  are  of  a  spe- 
cific gravity  greater  than  water;  and,  on  an  average, 
two-thirds  (according  to  the  quality  of  the  potato, 
fifty-five  to  seventy-six  per  cent.)  of  this  entire  dry 
substance  are  placed  to  account  of  starch.  We  can, 
therefore,  take  it  as  a  rule,  that  the  potato  must  have 
a  larger  specific  gravity  the  greater  its  amount  of 
starch.  The  finding  of  the  specific  gravity  of  the 
potato  may  be  accomplished  in  various  ways,  and  we 
will  here  elucidate  some  methods.  Before  we,  how- 
ever, consider  these  various  methods,  we  will  state, 
by  way  of  general  remark,  that,  from  the  determina- 
tion of  the  specific  gravity  of  a  few  potatoes,  no  con- 
clusion as  to  the  average  amount  of  starch  in  the 
whole  can  be  formed,  since  experience  has  proved  that 
the  single  parts  of  a  heap  of  potatoes  are  very  often 
very  varying  in  their  specific  gravity.  Hence  it  will 
be  necessary  to  determine  always  the  specific  gravity 
of  a  greater  quantity  of  potatoes,  and  thereupon  calcu- 
late the  value  of  the  material. 

A  very  convenient  method  for  determining  the  spe- 
cific gravity  of  potatoes  has  been  suggested  by  Fre- 


42  MANUFACTURE   OF    STARCH,    ETC. 

senius  and  Schulze,  and  by  their  method  the  determi- 
nation of  the  amount  in  potatoes  of  dry  substance  and 
starch  has  become  very  convenient  for  technical  pur- 
poses. Their  method  rests  upon  the  well-known  phy- 
sical law,  that  a  body  which  floats  in  a  liquor  in  such 
a  manner  that  it  neither  appears  entirely  uponjts  sur- 
face nor  sinking  under,  possesses  a  like  specific  gravity 
with  the  liquid  itself.  Resting  on  this  circumstance, 
the  determining  of  the  specific  gravity  of  the  potato  is 
carried  out  by  the  method  of  Fresenius  and  Schulze,  as 
follows: — 

A  concentrated  solution  of  common  salt  is  prepared 
of  about  three  parts  of  water  to  one  of  salt;  a  wide 
vessel  or  glass  is  filled  to  one-half  of  its  capacity  with 
water,  and  the  potato  to  be  examined  is  placed  therein, 
which,  on  account  of  its  greater  specific  gravity,  sinks 
to  the  bottom.  Thereupon,  some  part  of  the  concen- 
trated salt  solution  is  poured  into  the  glass,  while  con- 
stantly stirring,  till  the  potato,  resting  upon  its  bottom, 
gradually  rises  up,  and  finally  remains  floating  in  the 
liquor.  By  determining  the  specific  gravity  of  this 
salty  fluid  thus  made,  you  have  also,  by  means  of  a 
saccharometer,  .  the  specific  gravity  of  the  potato. 
If  we  now  desire  to  ascertain  the  starchy  value  of  the 
potato,  nothing  remains  to  be  done  but  to  look  for  the 
same  figure  contained  in  the  index  given  below,  which, 
as  indicated  by  the  hydrometer,  gives  the  specific 
gravity  of  the  salty  fluid,  respective  of  the  potato,  and 
the  figure  thus  found  is  the  specific  weight  of  the 
potato  analyzed. 

In  carrying  out  this  experiment,  care  is  to  be  taken 
that  no  air-bubbles  adhere  to  the  potatoes.  Should 
this  be  the  case,  they  can  be  easily  removed  by  the 
feathery  part  of  a  goose-quill.  If  the  potatoes  are 


THE   TECHNOLOGY    OF    STARCH. 


moistened  all  over  with  water  previous  to  placing 
them  in  the  glass,  such  bubbles  will  not  appear.  Care 
should  also  be  taken  that  the  liquid  for  determining 
the  specific  gravity,  by  means  of  the  saccharometer, 
retains  the  same  temperature  which  it  had  while  the 
potato  was  floating  therein. 

Table  for  ascertaining  the  Specific  Gravity  of  Potatoes,  founded 
upon  the  degrees  indicated  by  the  Saccharometer. 


Degree  of  the 
saccharometer. 

Specific 
gravity. 

Degree  of  the 
saccharometer. 

Specific 
gravity. 

Degree  of  the 
i  saccharometer. 

Specific 
gravity. 

14* 

.056 

20 

1.083 

25£ 

1.108 

15 

.061 

20£ 

1.085 

26 

1.110 

15* 

.063 

21 

1.088 

26* 

1.113 

16 

.065 

21* 

1.090 

27" 

1.115 

16| 

.068 

22 

1.092 

27£ 

1.118 

17 

.070 

22A 

1.094 

28 

1.120 

17* 

1.072 

23 

1.097 

28* 

1.122 

18 

1.074 

23A 

1.099 

29 

1.125 

18* 

1.077 

24 

1.101 

29£ 

1.1C7 

19 

1.079 

24£ 

1.103 

30 

1.129 

19* 

1.081 

25 

1.106 

Supposing  now  the  saccharometer,  when  placed  in 
the  salty  solution,  had  indicated  19|°,  the  specific 
gravity  of  the  solution,  and  hence  also  that  of  the 
potato,  would  be  1.081.  But  should  the  saccharometer, 
for  instance,  show  19f°,  the  specific  gravity  of  the 

potato,  in  this  case,  would  be  -  -,  ==  1.082. 

2i 

It  is  evident  that  the  specific  gravity  can  also  be  de- 
termined in  a  more  direct  way,  by  the  aid  of  a  hydro- 
meter (which  shows  the  specific  gravity  on  its  scale), 
or  by  weighing  in  a  flask  which  holds  one  hundred 
grammes  (3.5  ozs.)  of  water,  so  that  in  such  a  case  the 
above  table  can  be  dispensed  with. 

Fesca  has,  for  the  purpose  of  determining  the  specific 
gravity  of  potatoes,  constructed  a  particular  scale,  by 


44 


MANUFACTURE    OF    STARCH,    ETC. 


means  of  which  five  kilogrammes  (eleven  pounds)  of 
potatoes  can  be  weighed  at  once,  and  a  very  accurate 
determination  of  density  can  be  obtained.  This  scale 
is  arranged  as  delineated  in  Fig.  1. 


1. 


Fesca's  scale  for  determining  the  specific  gravity. 

The  vessel  a  is  filled  with  water,  until  the  latter 
runs  over  and  out  of  the  tube  &;  thereupon  the  wire 
basket  g  is  withdrawn  from  the  scoop  f  near  c,  and  is 
repeatedly  thrust  upon  the  bottom  of  the  reservoir  a, 
in  order  to  remove  all  the  air-bubbles  which  now  ad- 
here to  the  wire  basket,  and  the  scales  are  balanced  by 
placing  small  weights  on  the  scoop  d.  Now,  a  five 
kilogramme  (eleven  pound)  weight  is  placed  upon 
the  basin  e,  and  the  five  kilogrammes  of  potatoes 
which  are  to  be  weighed  are,  after  they  have  been  first 
thoroughly  brushed  off,  placed  in  the  basin  f,  but 
care  must  be  taken  to  prevent  the  potatoes  from  falling 
into  the  vessel  or  basket  g.  In  order  to  bring  the 
scales  into  perfect  balance,  the  last  potatoes  are  placed 
in  singly,  and,  if  necessary,  pieces  are  cut  off  from  one 
or  the  other  of  the  potatoes,  in  order  to  obtain  exactly 


THE  TECHNOLOGY  OF  STARCH. 


45 


five  kilogrammes  (eleven  pounds)  of  potatoes.  By 
this  operation  but  one  cut  surface  should  remain  on 
any  one  of  the  potatoes  (Fig.  2). 

Fig  2. 


Fesca's  scale  for  determining  the  specific  gravity.     Second  operation. 

In  order  to  find  the  weight  of  these  five  kilo- 
grammes (eleven  pounds)  of  potatoes  in  the  water,  or 
rather  to  find  the  weight  of  the  water  displaced  by 
the  potatoes,  the  potatoes  are  now  taken  from  the 
scale  f  and  placed  in  the  wire  basket  g  (without  re- 
moving the  five  kilogramme  weight  or  the  adjusting 
weights)  replacing  the  weight  in  the  scale  f  as  much 
as  is  necessary  to  balance  the  scales  (Fig.  3). 

Whereas  now  every  substance  placed  in  water 
weighs  so  much  less  as  the  water  of  a  like  volume 
displaced  by  such  substance  amounts  to,  the  weights 
placed  at  f  for  counterbalancing  are  equal  to  the 
weight  P  of  the  water  displaced  by  the  five  kilo- 
grammes of  potatoes.  This  weight  fluctuates  be- 
tween 4.421  (9.726  pounds)  and  4.717  kilogrammes 
(10.377  pounds),  but  is  accurately  ascertained  by  the 
use  of  suitable  weights,  even  to  the  fraction  of  .001 


46 


MANUFACTURE   OF    STARCH,    ETC. 


kilogramme  (.0022  pound).     The  specific   gravity  of 
the  potatoes  is  obtained  through  the  division  of  the 


Fie.  3. 


Fesca's  scale  for  determining  the  specific  gravity.      Third  operation. 
Determination  of  the  weight  of  water  displaced  by  the  potatoes. 

weight  of  the  potatoes  (five  kilogrammes)  by  that  of 

5 
the  displaced  water  (P),  and  hence  is  equal  to  -— .     In 

order  to  obtain  correct  results  the  following  rules 
should  be  strictly  observed:  Prior  to  transferring  the 
potatoes  from  the  bowl  f  into  the  basket  #,  they  are 
washed  arid  brushed  clean.  This  is  done  in  order  to 
moisten  every  part  of  the  potatoes  in  such  a  manner 
that  no  air-bubbles  can  adhere.  Thus  moistened,  the 
potatoes  are  placed,  one  after  the  other,  in  the  wire 
basket.  Should  some  of  them  be  found  lighter  than 
water,  then  they  are  to  be  covered  by  the  heavier  ones, 
so  as  to  cause  them  to  remain  under  water.  The  po- 
tatoes must  be  entirely  covered  by  water.  The  water 
to  be  applied  must  be  rain  or  distilled  water;  potatoes 
and  water  must  be  of  the  same  temperature  as  the  room 
is  where  the  operation  takes  place,  and  hence  they 
ought,  previous  to  being  weighed,  to  be  placed  in  that 


THE  TECHNOLOGY  OF  STARCH.         47 

room.  The  water  reservoir  and  the  scales  have  to  be 
placed  so  that  the  wire  basket  does  not  touch  the  sides 
or  the  bottom  of  the  former. 

THE  MANUFACTURE  OF  POTATO  STARCH. 

For  producing  starch  from  tubers  generally  two 
methods  are  known,  which  essentially  differ  in  prin- 
ciple. The  first  method,  more  commonly  applied, 
which  is  known  as  the  "older  method,"  consists  of  the 
grating  of  the  tubers  into  the  finest  possible  parts,  by 
means  of  graters  or  such  like  apparatus.  A  fine  pulp 
is  prepared,  washed  out  in  sieves,  or  rather  brushed 
through  the  meshes  of  the  sieves,  while  allowing  the 
free  flow  of  water  through  the  same,  and  thereby 
separating  the  starch  from  the  drained-off  milky 
liquid.  The  starch  obtained  in  this  simple  manner 
is  thereupon  purified,  either  by  washing  it  out  or  by 
applying  centrifugal  force  for  cleansing,  then  dried  in 
drying-rooms,  where  a  high  degree  of  temperature  is 
maintained,  and,  finally,  the  substance  is  crushed 
(bruised)  between  rollers. 

The -second  method,  known  as  Voelker^s  process,  con- 
sists in  first  opening  the  cellular  tissues  of  the  tubers 
in  a  chemical  way.  For  this  purpose  the  potatoes  are 
first  cut  in  slices,  macerated  in  tepid  water,  then  piled 
up  in  heaps  of  several  feet  high,  and  thus  left  undis- 
turbed for  about  eight  days,  whereby  the  temperature 
increases  to  about  40°  C.  (104°  F.).  In  consequence 
of  this  spontaneous  heating,  in  fact,  putrefying  of  the 
potatoes,  some  chemical  transformations  occur  in  the 
tissues  of  the  tubers,  which  have  not  as  yet  been  suffi- 
ciently investigated,  but  they  undoubtedly  result  from 
the  formation  of  a  matter,  which  not  only  dissolves  the 
intercellular  substance  of  the  starch-containing  tissue, 


48  MANUFACTURE    OF    STARCH,    ETC. 

but  also  affects  the  cellular  textures  and  partly  dissolves 
them.  This  is  probably  caused  by  the  formation  of 
organic  acids  ensuing  during  this  process,  and  which 
dissolve  the  intercellular  substance  which  is  com- 
posed of  pectine  bodies.  The  chemical  process,  how- 
ever, which  causes  the  solution  of  the  cellular  textures 
is  still  entirely  problematical,  as  this  chemical  process 
has  not  yet  been  thoroughly  investigated  by  scientific 
men.  The  putrefaction  having  amply  progressed,  and 
the  fibrin  having  lost  its  cohesive  property,  in  so  far  as 
to  transform  the  potato  substance  into  a  soft  dough- 
like  mass,  then  a  complete  separation  of  the  starch 
by  mechanical  means  may  be  carried  on  with  ease. 
To  this  end,  the  substance,  which  beside  starch  also 
contains  fibrin  and  skin  (forming  a  paste-like,  loose 
mass),  is  mixed  with  plenty  of  water,  and  strained 
through  a  coarse  sieve,  whereby  the  coarsest  parts  are 
retained.  The  separating  of  the  finer  parts  is  there- 
upon caused  by  application  of  fine  hair  or  wire  sieves, 
whose  meshes  are  so  fine  as  to  pass  only  the  finest 
starch  and  finely  broken  up  fibre  parts.  The  sepa- 
rating of  the  starch  from  the  fibre  parts  is  finally 
accomplished  by  the  application  of  a  very  ingeniously 
constructed  washing  apparatus. 

We  will  now  consider  these  methods  of  manufac- 
turing starch  in  detail,  as  applied  in  practical  usage. 
The  fabrication  of  potato  starch  by  the  older  method 
is  divided  into  the  following  operations: — 

a.  The  washing  of  the  potatoes. 

b.  The  grating. 

c.  The  washing,   separating    the    starch   from    the 

pulp. 

d.  The  washing  out  and  refining  of  the  starch. 

e.  The  drying  of  the  starch. 


THE  TECHXOLOGY  OF  STARCH.         49 

The  Cleaning  of  the  Potatoes. — The  potatoes  are 
washed,  in  order  to  remove  earthy  substances  and  small 
stones  which  adhere  to  them,  and  are  frequently  of  the 
same  shape  and  color  as  the  tuber,  but  very  injurious 
to  the  grating  machine.  This  cleansing  is  easily  accom- 
plished when  the  potato  grows  .in  a  sandy  soil,  but  it 
is  more  difficult  and  requires  much  time  when  the 
potatoes  were  raised  in  a  heavy  clay  soil,  as  the  tubers 
will  then  have  on  their  surface  many  deep  penetrating 
points  (tubercles).  The  removal  of  the  slimy  earth 
particles  must  be  carefully  done,  since  they  not  only 
injure  the  quality  of  the  starch,  but  also  lessen  the 
yield  of  it  as  a  first  class  article. 

In  all  of  the  larger  starch-manufacturing  establish- 
ments an  apparatus  is  expressly  in  use  for  this  pur- 
pose, in  the  form  of  a  cylinder.  Of  these  contrivances 
there  are  quite  a  large  variety,  but  we  select  for  our 
use  and  delineation  one  of  the  latest  and  of  the  best 
construction. 

Venuleth's  washing-machine  (Figs.  4  and  5)  is  an 
excellent  apparatus,  by  means  of  which   part  of  the 
dross  is  removed  from  the  potatoes  by  the  process  of 
dry-sifting.     It  consists  of  the  following  parts :   a,  A 
conical  iron-drum,  provided  with  a  basket  for  trans- 
mission; &,  a  long  square  iron  case  with  beds  for  the 
strong  iron  shaft  c;  dd  are  the  cross-branches  sup- 
plied with  wooden  beaters;  ee,  the  iron  grate,  com- 
posed of  three  parts,  so  as  to  be  able  to  take  it  out 
when  cleaning  the  entire  machine  \f  is  a  semicircular 
box  for  receiving  the  washed  potatoes;  g  is  the  wheel 
for  drawing   up    the  water  (bucket  wheel),  and   by 
which  the  washed  potatoes  are  dispatched  to  the  box/; 
h  is  an  opening  for  the  flowing  out  of  the  wash  and 
waste  water,  worked  by  a  slide  with  a  handle. 


50 


MANUFACTURE    OF    STARCH,    ETC. 


"Ven ul eth's  apparatus  is,  as  is  shown  by  Figs.  4  and 
5,  supplied  with  an  elevator  (endless  chain  with  pump- 
work),  which  makes  it  possible  to  send  the  washed 
potatoes,  without  the  use  of  manual  labor,  in  a  direct 


Fig.  4. 


Potato  •washing-machine  with  elevator. 

and  continuous  way  to  the  grating  machine  in  the 
upper  story.  The  elevator  itself  consists— for  the 
working  of  the  elevator-chain  and  washing  machine 
— of  a  lower  wheel,  i,  and  an  upper  elevator- wheel,  Jc. 
By  II  I  the  elevator-chain  is  shown,  while  in  m  m  rep- 
resent the  pump  boxes,  which  latter  are  filled  at  / 
with  potatoes,  in  order  to  re-deposit  them  above  directly 


THE  TECHNOLOGY  OF  STARCH.         51 

into  the  hopper  of  the  grating  machine;  n  is  the 
counter  shaft ;  o  o,  two  movable  beds  to  tighten  the 
elevator  chain ;  p  p,  u  fast  and  loose  belt  drums" 
(pulleys)  for  moving  the  machine.  In  further  de- 
scribing this  machine,  we  notice  in  front  of  it  the 
board  g  which  is  inserted  into  the  apparatus.  By  this 
board  the  potatoes  are  at  once  caused  to  sink  below 
the  surface  of  the  water,  immediately  after  their 
reception  in  the  washing  box,  since  all  the  potatoes 
can  only  enter  the  actual  space  for  washing,  through 
the  opening  situated  under  this  board.  During  the 
process  of  washing,  the  potatoes  are  placed  in  the 
preparing  drum  a,  where  they  are  sifted  in  a  dry  way, 
and  in  this  manner  are  already  freed  from  a  large  part 
of  the  earth  adhering  to  them.  From  the  preparing 
drum,  they  are  forwarded  to  the  washing  box,  where 
they  are  "beaten"  while  water  is  constantly  flowing 
in;  from  thence  they  are  gradually  pushed  into  the 
drum  g.  Meantime,  the  stones,  gravel,  sand,  and 
dirt  sink  to  the  bottom,  and  can  be  removed  from  the 
box  through  the  opening  placed  therein  for  this 
purpose. 

The  washed  potatoes  fall  from  the  ejecting-box  into 
the  semicircular  storage-box,  f,  and  are  there  received 
by  the  small  elevator-cases,  m  m,  and  sent  up  to  the 
grater. 

The  greater  the  care  taken  in  washing  the  potatoes, 
the  nicer  and  whiter  will  be  the  starch  produced  from 
them ;  otherwise  it  would  be  almost  impossible  to  re- 
move the  earthy  particles — especially  the  red  or  gray 
colored  dross — which  might  mix  with  the  starch  and 
with  the  same  precipitate  to  the  bottom  of  the  vessel 
used. 


52  MANUFACTURE.  OF    STARCH,    ETC. 

Grinding  (gtating}  of  the  Potatoes. — The  grinding 
or  grating  of  the  potatoes  disrupts  the  cellular  tissues, 
wherein  the  starch  granules  are  situated,  and  thus 
lays  bare  as  far  as  possible  the  starch  substance. 
This  task,  however,  can  never  be  perfectly  accom- 
plished by  a  mechanical  operation,  and  should  for 
many  reasons,  which  we  will  mention  below,  never  be 
attempted.  Notwithstanding  this,  the  general  opinion 
prevails,  that  the  finer  the  potatoes  are  grated  the 
more  cells  are  opened,  and  the  greater  will  be  the 
yield  in  starch.  Hence,  the  grinding-machine  is  the 
most  important  apparatus  for  the  manufacture  of 
potato-starch.  That  the  machines  at  present  used 
for  this  purpose,  do  not  completely  and  satisfactorily 
fulfil  it,  becomes  manifest,  since  all  starch  manufac- 
tories do  not  use  the  same  machine  for  grating. 

The  machines  used  for  the  grinding  of  potatoes 
are  of  various  sizes,  and  quite  a  number  of  such  con- 
trivances are  in  vogue,  from  the  simple  hand  grater 
to  the  latest  construction  of  Champonnois,  whose 
"grater"  is  at  present  the  best  known  one. 

The  working  capacity  of  this  grater  amounts  in 
24  hours  to  a  production  of  about  25,000  kilogrammes 
(55,000  Ibs.)  of  potatoes.  Wherever  a  homogeneous 
mass  is  desirable  the  application  of  this  machine  will 
be  of  the  greatest  advantage. 

By  means  of  the  eccentric  0,  which  by  turning 
presses  against  the  wheel  belonging  to  an  extension 
of  the  lever  E,  a  rapid  back  motion  of  tjie  buffer  B  is 
accomplished;  the  forward  pushing  of  the  same  and 
the  pressing  of  the  potatoes  against  the  grater  are 
performed  by  means  of  the  weight  F,  whose  pressure 
can  be  increased  or  decreased,  by  displacing  the  parts 
of  the  lever.  This  is  regulated  according  to  the  con- 


THE  TECHNOLOGY  OF  STARCH.         53 

strnction  of  the  teeth  of  the  saw,  or  the  nature  of  the 
potatoes. 

Fig.  6. 

m 

D 


Champonnois's  grater  with  mechanical  buffers. 
Fig    T. 


Champonnois's  grater  of  latest  construction. 

The  potatoes  are  placed  in  the  mill -hopper  J,  the 
two  flyers  F F  revolve  with  a  velocity  of  from  800 


54  MANUFACTURE    OF    STARCH,    ETC. 

to  1000  revolutions  per  minute  around  the  axis  (?, 
take  hold  of  the  potatoes  and  force  them  with  the 
velocity  of  their  rapid  turning  towards  the  teeth  in 
the  drum,  whereby  they  are  macerated  and  changed 
into  a  fine  paste.  The  points  of  the  sawblades  are 
very  short,  and  extend  but  0.5  mm.  (0.020  inch)  above 
the  drum-surface.  During  their  use,  they  become 
after  a  short  time  bent,  inasmuch  as  the  potatoes  are 
incessantly  hurled  with  great  velocity  against  them, 
and  always  in  the  same  direction.  For  this  reason,  the 
shaft  is  allowed  to  run  in  a  reverse  direction — after  the 
grater  has  run  for  half  a  day  or  so — and  thus  forcing 
the  potatoes  against  that  side  of  the  teeth  which  have 
previously  been  bent.  After  48  hours'  use,  the  teeth 
usually  become  entirely  dull  and  must  be  resharpened. 

Finally,  it  should  be  mentioned  that  great  care  must 
be  taken  to  keep  the  grater  and  reservoir  absolutely 
clean.  This  is  of  the  utmost  importance;  remnants 
should  never  be  allowed  to  remain  long  in  the  box,  since 
in  this  finely  divided  paste,  on  account  of  the  influence 
of  the  atmosphere,  a  decomposition  will  soon  ensue.  It 
will  be  profitable  to  apply  the  smallest  possible  receiver, 
which  compels  the  workmen  to  perform  a  quicker  opera- 
tion in  shovelling  away  the  grated  potatoes  thrown  out 
by  the  machine.  Both  grater  and  receiver  should  be 
thoroughly  cleaned  every  six  hours,  and  be  washed  out 
with  clear  cold  water,  and  thus  prevent  sourness. 

The  Operation  of  Washing  (Sifting},  Separating  the 
Starch  from  the  Paste. — The  paste  furnished  by  the 
grating  consists  of  diluted  fruit-juice  (sap),  freed 
starch-granules,  cellular  substance  and  fine  fibres  of 
potato  substance  whose  cells  have  not  been  opened  by 
the  grater,  which  hence  still  inclose  starch-granules. 
For  separating  the  starch-granules,  i.  e.,  loosening  the 


THE   TECHNOLOGY   OF    STARCH. 


55 


starch  from  the  cellular  substance,  sifting  apparatus 
of  the  most  varied  kinds  are  used,  in  which  the  paste 
is  treated  while  water  is  constantly  pouring  on.  The 
starch-granules  pass  through  the  meshes  of  the  sieve, 
while  the  fibrous  substance — the  so-called  pulp — re- 
mains in  it. 

The  most  simple  apparatus  of  this  kind,  which  is, 
however,  merely  used  for  manufacturing  starch  on  a 
limited  scale,  consists  of  a  common  sieve  of  fine  meshes 
either  of  wire  or  horsehair,  which  is  placed  in  a  tub 
or  box  filled  with  water.  The  sieve  rests  on  two 
ledges  fixed  in  such  a  manner  as  to  give  the  sieve  an 
inclined  position,  so  as  to  be  enabled  to  push  the  same 
into  the  water,  or  by  turning  to  raise  it  up  at  will. 

•Fig.  8. 


Cylinder  sieve  with  brushes. — Seeles  &  Co.  constructors. 

The  paste,  is  put  in  but  small  portions  into  the 
sieve,  and  worked  either  by  hand  or  by  means  of 
brushes,  and  alternately  above  or  below  the  water, 
until  by  the  pressing  out  of  the  residuum,  starch  no 
longer  appears  in  the  drained-off  water.  The  starch 


56 


MANUFACTURE   OF    STAKCH,    ETC. 


bo 

E 


05 

b*0 


THE  TECHNOLOGY  OF  STARCH.         57 

sinks  rapidly  into  the  water,  or  rather  into  the  greatly 
diluted  vegetable  juice,  so  that  a  large  quantity  of  the 
grated  paste  can  be  washed  out  before  a  renewal  of  the 
water  becomes  necessary. 

As  for  this  manipulation  too,  a  great  number  of 
machines  have  been  in  use,  most  of  which  were  more 
or  less  defective.  Siemens  invented  the  'bolting -sieve. 
He  has  improved  the  apparatus  of  older  construction 
so  completely,  that  neither  with  regard  to  the  water- 
supply,  nor  with  regard  to  the  washing  of  the  potato- 
paste  does  this  sieve  leave  anything  to  be  desired. 

In  Figs.  9  and  10  we  present  Siemens's  bolting-sieve 
of  the  latest  construction,  both  in  longitudinal  and 
lateral  section  (diagram). 

Upon  a  simple  wooden  framework  a,  the  grating 
cylinder  &,  is  fastened,  from  which  the  potato-paste 
falls  directly  upon  the  jolting  sieve  or  bolting  appa- 
ratus c  c,  which  by  means  of  bars  d  d  d,  is  connected 
with  the  framework.  The  grating  cylinder  receives  its 
motion  from  the  driving  pulley,  e  (e'  is  the  loose  pulley). 
The  roller  f  transmits  the  motion  of  the  cylinder  to 
the  pulley  g,  and  through  this  crank  spindle  h  is  set 
in  motion,  which  by  means  of  the  bar  i  is  in  connec- 
tion with  the  shaker-sieve. 

The  advantages  of  Siemens's  shaker-sieve  are  essen- 
tially the  following :  Through  the  cavities  of  the  boxes 
placed  upon  the  sieve,  a  pushing  together  (accumula- 
tion) of  the  potato-paste  upon  the  surface  of  the  sieve 
is  avoided,  and  moreover  a  large  waste  of  water  is 
prevented,  since  this  no  longer  uselessly— as  was 
formerly  the  case — runs  off  over  those  parts  of  the 
sieve  which  are  not  covered  with  paste.  By  the  use 
of  this  apparatus  the  paste  in  the  cavities  forced  by 
water  will  help  to  cover  evenly  the  surface  of  the  sieve 


58  MANUFACTURE   OF    STARCH,    ETC. 

whereby  the  too  rapid  flow  of  the  water  through  the 
sieve  becomes  almost  impossible.  Such  an  apparatus 
with  a  sieve  of  3.3  metres  (10.8  feet)  length,  and  30  cen- 
timetres width  (11.8  inches),  consisting  of  eight  pieces 
of  sieve  and  as  many  boxes,  is  sufficient  to  completely 
wash  out  the  paste  of  from  400  to  500  kilogrammes 
(880  to  1100  Ibs.)  of  potatoes  per  hour.  In  order  to 
increase  the  yield  of  starch  from  potatoes,  Siemens 
makes  use  of  stone  rollers,  which  revolye  with  unequal 
rapidity,  and  thus  operate  in  both  bruising  and  grind- 
ing. The  paste  runs  off  from  the  shaker-sieve,  and  the 
freed  starch,  in  greater  part  already  washed  out,  can 
be  conducted  into  the  receiving  tank,  while  the  former 
is  crushed  very  fine  by  the  rollers,  and  thereupon  con- 
ducted to  the  so-called  extracting  machine  upon  which 
its  total  exhaustion  is  rendered  complete. 

The  Edulcoration  and  Refining  Process. — The  starch 
separated  in  one  or  the  other  way  from  the  potato, 
sinks  in  the  liquid— a  diluted  fruit-juice—rapidly  and 
settles  upon  the  bottom,  so  that  the  brownish  liquid 
may  be  soon,  and  moreover  completely,  drawn  off.  But 
in  this  condition  as  the  starch  deposits  itself  in  the 
tanks  or  walled-in  cisterns  (Sedimenteurs),  it  is  by  no 
means  yet  pure,  but  contains  impurities  such  as  parti- 
cles of  clay,  finely  divided  cellulose,  etc.,  and  chemically 
mixed  with  various  other  substances,  as  albumen,  slime, 
rosin,  fat,  etc.,  from  the  potatoes.  These  impurities, 
which  in  the  solid  deposit  of  the  starch  are  contained 
in  but  proportionately  small  quantities,  are  partly  so- 
luble in  water  alone  (as  albumen,  slime)  and  others  in- 
dissoluble, so  these  may  be  extracted  with  alcohol  and 
ether  (as  rosin  and  oil).  These  latter  substances, 
which  are  only  soluble  in  alcohol  and  ether,  impart  to 
the  starch  the  objectionable  property  of  becoming,  after 


THE  TECHNOLOGY  OF  STARCH.         59 

drying,  a  firm  coherent  mass,  while  starch  completely 
free  from  these  admixtures  (rosin  and  oil),  in  the  pro- 
cess of  drying,  would  of  itself  break  into  a  fine  powder. 

The  washing,  as  also  the  edulcoration  of  the  starch, 
however,  is  not  generally  to  be  extended  to  the  re- 
moval of  the  substances  which  are  not  soluble  in 
water  of  which  there  is  only  a  very  small  quantity,  but 
it  suffices  simply  to  thoroughly  remove  the  common 
admixtures,  and  those  impurities  which  are  easily  so- 
luble in  wrater.  The  latter  are  extracted  simply  by 
repeatedly  renewing  the  wash  water  and  are  thereby 
removed  in  solution,  while  the  common  admixtures  in 
consequence  of  their  inferior  specific  gravity,  or  their 
finer  particles,  form  a  scum  which  may  easily  be  taken 
off  by  stirring  up  with  water  the  deposited  starch,  upon 
which,  in  the  first  place,  these  particles  settled. 

After  the  starch  has  sufficiently  deposited  itself  in 
the  " Sedimentewr,"  the  water  standing  over  the  starch 
— containing  salt  and  albumen — is  drained  off,  and  the 
thick  starch-substance  conducted  into  a  large  starch- 
washing  tank  (Laveur),  the  empty  space  remaining 
filled  up  with  pure  water.  In  order  to  ascertain  the 
correct  quantity  of  water  necessary  for  this  purpose 
and  to  obtain  a  starch-milk  which  is  neither  too  thick 
nor  too  thin,  the  height  of  the  starch  strata  in  the 
"laveur"  is  first  ascertained  and  thereupon  filled 
up  with  water  to  the  third  part  of  the  ascertained 
height.  If,  for  instance,  the  height  of  the  starch  layer 
is  33  cm.  (13  inches),  the  quantity  of  water  to  be  al- 
lowed to  flow  upon  the  starch  is  ^3  =  11  cm.  (-1.33 
inches),  height. 

To  do  this  efficaciously  a  simple  measuring  apparatus 
has  been  constructed  by  Markl,  the  use  of  which  may 
be  easily  learned  from  our  representation  (Fig.  11). 


60 


MANUFACTURE   OF    STARCH,    ETC. 


On  the  ends  of  the  measuring-gauge,  which  is  of  the 
same  height  as  the  "laveur,"  are  two  movable  ledges, 
which  by  means  of  screws  can  be  fastened.  The 
gauge  is  from  above  to  below  divided  and  numbered 

Fig.  11. 


Markl's  apparatus  for  measuring  the  height  of  the  starch-strata  in  the  tank. 

into  equal  degrees,  for  instance  into  centimetres. 
The  same  numbering  commences  from  below ;  but  the 
single  divisions  are  but  one-third  as  large.  If  the  gauge, 
as  is  delineated  in  the  illustration,  is  sunk  down  to  the 
level  of  the  starch,  and  the  upper  ledge  brought  down 
to  the  top  of  the  laveur,  the  extending  space  of  the 
ledges  will  show  upon  the  scale  the  height  of  the  starch- 
strata  in  centimetres.  It  is  then  only  necessary  to  push 
the  lower  ledge  up  to  the  same  figure,  and  fastening 
it  by  drawing  the  screw  tight,  you  can  thereupon  ad- 
mit the  flow  of  water,  until  the  water  level  is  of  equal 


THE  TECHNOLOGY  OF  STARCH.         61 

height  with  the  upper  surface  of  the  lower  ledge, 
which  is,  for  convenience  sake,  painted  black. 

Another  method  for  cleaning  the  impure  starch, 
consists  in  stirring  the  same  in  a  tank  filled  with 
water,  which  is  supplied  with  a  stirring  apparatus, 
and  by.  draining  off  the  milky  liquid  by  means  of  a 
spigot  in  a  thin  stream,  and  leaving  it  to  flow  through 
long  slightly  inclined  gutters  (so-called  elutriating 
chines)  of  about  60  centimetres  (23.6  inches)  in  width 
and  16  centimetres  (6.3  inches)  in  depth.  This  can 
also  be  accomplished  with  still  greater  facility,  by  run- 
ning the  starch  upon  the  upper  part  of  the  gutter  and 
pouring  water  over  it  through  the  same  watering  ap- 
paratus, which  is  provided  with  a  finely  perforated 
spout.  While  the  very  thin  starch-milk — produced  in 
one  way  or  another — flows  over  the  inclined  plane, 
the  denser  starch  will  deposit  itself  near  the  tank, 
at  a  greater  distance,  a  less  pure  article,  and  the  spe- 
cifically lighter  substances  will  reach  the  end  of  the 
gutter,  and  there  drain  off  w.ith  the  water.  By  apply- 
ing thumb-screws,  the  incline  of  these  gutters  may  be 
regulated. 

The  construction  of  such  an  inclined  plane  (elutria- 
ting machine)  is  sketched  in  Figs.  12  and  13. 

The  gutter  has  a  slight  incline  of  about  1|  milli- 
metres (0.06  inch),  per  metre  (39.37  inches)  in  length. 
Underneath  this  gutter  two  more  gutters,  D  -27 and  GF, 
of  the  same  length  and  of  the  same  incline,  are  placed, 
of  which  the  middle  one  is  fixed  to  run  in  an  opposite 
direction,  the  lower  one  (G  F)  in  the  same  direction 
as  the  top  one.  From  a  very  finely  perforated  metal 
plate  (rose),  S,  a  fine  jet  of  water  is  continually  flowing 
— by  opening  the  cock  H — on  the  accumulated  starch. 
The  cock  is  situated  at  the  upper  end  of  the  top  gutter 


62 


MANUFACTURE   OF    STARCH,    ETC. 


(A).  The  starch  is  continually  stirred  with  a  rake. 
The  water  will  gradually  carry  off  all  the  starch,  and  in 
consequence  of  its  running  smoothly  and  slowly  will 
again  deposit  the  pure  starch  in  the  gutters  D  E  and 


(Front  view.) 
Inclined  plane  (elutriating  machine)  for  refining  the  slimy  starch,  etc. 

G  F,  while  the  lighter  particles  remain  suspended  in 
the  water,  and  along  with  some  starch  finally  flow  oft 
through  the  gutters  JJ,  into  one  of  the  tanks,  II H'  or 
JET.  In  these  tanks  all  will  be  redeposited  in  layers, 
whatever  the  liquid  has  carried  off,  and  from  this  de- 
posit the  pure  starch  may  be  easily  separated,  and  the 
muddy  dross  starch  which  again  accumulates  be  refined 
by  repeating  the  operation  on  the  inclined  plane.  The 
refining  of  starch  by  means  of  the  inclined  plane  is  so 
convenient  and  requires  so.  little  labor  and  outlay,  that 
in  modern  times,  in  most  of  the  larger  establishments, 
these  described  inclined  planes  find  general  application, 


THE  TECHNOLOGY  OF  STARCH.         63 

in  lieu  of  tanks,  for  the  washing  and  refining  of  starch. 
By  a  manipulation  of  200  hectolitres  (567.500  bushels) 
of  potatoes  in  twelve  working  hours,  a  gutter  of  80 
metres  (262.4  feet)  in  length,  and  1.1  metre  (3.6  feet) 
in  width,  with  an  inclination  of  from  1  to  1.5  milli- 
metres (.039  to  .059  inch)  per  length  metre  (3.28  feet) 
is  required.  For  greater  convenience  the  gutter  is 
divided  into  three  parts  of  equal  length,  as  is  shown 
by  Fig.  12,  and  these  parts  are  placed  above  each 
other. 

The  lower  part,  F  G,  of  this  gutter  is  placed  on  the 
ground  floor  of  the  factory,  -and  is  either  neatly  walled 
in  cement  or  inclosed  by  a  layer  of  asphaltum.  The 
middle  section  of  the  gutter,  D  (7,  is  of  wood,  as  also 
the  upper  one,  AB.  The  two  upper  gutters  have  for 
a  foundation  a  strong  timber  frame,  and  their  corres- 
ponding distance  is  the  same  as  that  between  the  lower 
and  middle  gutter,  equal  to  60  centimetres  (1.97 
feet).  The  incline  of  the  two  upper  gutters  can  be 
regulated  at  will,  and  to  this  end  serve  the  axes  EE1, 
of  the  gutters,  which  rest  firmly  on  the  timber  frame. 
The  gutters  can  be  turned  around  these  axes  to  suit, 
and  by  dint  of  a  greater  or  less  incline,  which  is  im- 
parted thereby  to  the  gutters,  the  flow  of  the  liquid 
in  the  same  may  be  accelerated  or  retarded.  For 
regulating  the  level  of  the  liquid  in  the  gutters,  the 
valves  B  and  D  serve ;  this  becomes  requisite  as  soon 
as  a  certain  quantity  of  starch  has  been  deposited  in 
the  gutters. 

The  working  of  this  apparatus  is  very  simple.  The 
starch-fluid — suificiently  diluted  with  water — flows 
from  a  receiver  by  A  to  the  highest  part  of  the  top 
gutter.  The  further  motion  of  the  liquid  ensues  very 
slowly,  so  that  the  heavier  starch  is  deposited  into  the 


61  MANUFACTURE   OF    STARCH,    ETC. 

upper  gutter,  while  the  lighter  fibres  remain  suspended, 
and  flow  on,  over  gutters  C  D  and  F  £?,  and  empty 
into  the  cistern  G. 

Fig.  1 4. 


Inclined  plane  for  refining  starch.     (Longitudinal  section.) 

Hence  the  greater  part  of  the  starch  is  deposited  in 
the  upper  part  of  the  gutters  A^  B,  which  for  this  reason 
must  be  cleared  after  each  twelve  working  hours;  the 
middle  part,  C  D,  is  cleared  but  twice  a  week,  the 
lower  part,  E  F,  but  once  in  every  week,  since  in  these 
parts  the  starch  collects  but  very  slowly.  The  starch 
as  taken  from  the  gutters,  although  sufficiently  pure 
for  some  commercial  purposes,  is,  on  account  of  the 
small  quantities  of fruit- sap  still  adhering  to  it,  gene- 
rally preferred  to  be  washed  out  again  with  pure  water 
in  the  depositing  tanks.  This  last  process  of  refining, 
is  however  accomplished  much  easier  and  requires  a 
much  less  number  of  "  Sedimenieurs," — six  to  eight  are 
amply  sufficient — with  the  application  of  the  inclined 
plane.  Formerly,  when  the  above  described  machin- 
ery was  not  yet  known,  the  starch  manufactories  re- 


THE    TECHNOLOGY    OF    STARCH.  65 

quired  for  the  refining  of  starch  quite  a  large  number 
of  tanks  which  not  only  used  up  much  space,  and  were 
also  very  expensive,  but  moreover  necessitated  much 
labor  and  it  caused  a  great  deal  of  inconvenience  to 
keep  them  clean  and  pure.  In  recent  times  centri- 
fugal machines  or  conical  drums  have  been  constructed 
for  the  refining  of  starch,  which  Fesca  terms  "  Re- 
fining Centrifugues."  The  inventor,  -Albert  Fesca, 
discovered  first,  that,  from  the  starch  milk  in  the  pro- 
cess of  centrifuguing,  the  substances  suspended  therein 
will  deposit  themselves  on  the  sides  of.  the  drum  by 
turns  according  to  their  weight  and  specific  gravity, 
i.  e.,  at  first  the  larger  starch  granules,  then  the  smaller, 
and  finally  the  dross  and  fibrous  substance,  in  such 
a  manner  that  the  latter  forms  a  strictly  separate  layer 
which  may  easily  be  taken  off  from  the  white  starch 
strata.  The  centri  fugue  may  thus  serve  not  merely 
for  draining  off  the  water,  but  also  for  purifying  the 
starch.  Fesca's  refining  centrifugue  distinguishes 
itself  from  the  common  centrifugues  by  its  drum 
being  inside,  divided  by  means  of  diametrical  parti- 
tions into  six  sections,  into  which  suitable  boxes  are 
placed  which  correspond  to  the  sides  of  the  drum,  and 
are  lined  with  cloth.  During  the  centrifuguing  of  the 
starch-milk  in  this  apparatus,  six  starch  cakes  will  be 
formed  in  the  box-shaped  insets  from  which,  after  they 
have  been  taken  out,  the  scum  may  be  conveniently 
removed.  In  order  to  facilitate  the  placing  in  and 
withdrawing  of  these  boxes  from  the  drum  the  upper 
edges  of  the  same  are  not  riveted  but  screwed  on. 
Every  centrifugue  is  furnished  with  two  drums,  both 
of  which  fit  upon  the  axes,  and  while  one  of  ,  the  same 
is  put  in  place  and  in  operation,  the  other  is  being 


THB 

WV*»  TW  W  T*  C?TfH  TT 


66  MANUFACTURE    OF    STARCH,    ETC. 

emptied  and  again  prepared  for  the  purpose  of  centri- 
fuguing. 

The  construction  of  centrifugues  generally  is  essen- 
tially as  follows :  On  the"  upper  end  of  a  vertical  spindle 
a  drum  of  copper  or  sheet-iron  open  from  above  is 
fastened,  upon  its  bottom  is  riveted  a  cone  of  copper  or 
cast-iron,  while  the  sides  of  the  drum  are  perforated  and 
supplied  with  a  double  sieve  of  brass  wire,  the  outer 
sieve  being  coarse  while  the  inner  is  of  finer  texture. 
By  means  of  turning  the  spindle  the  drum  is  put  into 
swift  rotation,  and  during  this  operation  the  starch 
mixed  with  water  is  placed  therein.  The  mass  de- 
scends in  the  first  place  upon  the  cone  which  extends 
into  the  drum,  but  immediately  thereafter,  in  conse- 
quence of  the  centrifugal  power,  is  hurled  from  the  sur- 
face of  the  cone  in  all  directions  against  the  surround- 
ing sides,  and  equally  distributed  in  thick  layers.  By  a 
continuous  and  rapid  revolution  of  the  drum,  the  liquid 
part  (the  water)  of  the  starch  flour  is  hurled  or  pressed 
through  the  rneshes  of  the  sieve,  while  the  solid  starch 
granules,  which  cannot  pass  through  the  finer  sieve,  are 
kept  back.  The  water  which  is  hurled  out  with  great 
vehemence  is  caught  by  a  casing  (jacket)  of  iron 
plate  which  surrounds  the  inside  drum  and  from  thence 
is  conducted  out. 

In  order  to  secure  for  the  centrifugue  a  successful 
action,  a  quiet  motion  of  the  same  without  rocking  to 
and  fro  is  absolutely  requisite.  This  condition  will  be 
most  perfectly  accomplished  by  fixing  the  entire- 
mechanism  for  motion  beneath  the  apparatus.  The 
spindle  of  the  drum  is  so  arranged  as  to  move  in  the 
hollow  (indentation)  of  a  sphere,  and  by  a  so-called 
buffer-bed  guide  will  yield  in  every  direction  to  the 
pressure.  The  axis  will  thereby  be  enabled  to  cause 


THE  TECHNOLOGY  OF  STARCH. 


G7 


the  centri  fugue  when  in  motion  to  choose  its  own  di- 
rection, which  may  correspond  to  the  eccentric  course 
of  its  point  of  gravity. 


i<?.  15. 


(Vertical  section.) 
Fig.  16. 


(Ground  section.) 
Fesca's  centrifugal  machine. 


68  MANUFACTURE   OF    STAHCH,    ETC. 

In  Figures  15  and  16,  is  delineated  one  of  the 
most  excellent  centrifugal  machiiies  Voth  in  a  vertical 
design,  and  from  below.  The  drum  T  is  made  of  a  f 
centimetre  (0.295  inch)  thick  sheet-iron  plate,  and  is 
thus  of  a  heavy  weight,  which  is  of  great  importance 
during  the  moment  the  starch  milk  is  poured  into  the 
drum,  and  to  cause  an  equal  rotation  of  the  latter. 

The  drum  T  runs  independently,  and  is  supplied 
with  a  motion  from  below.  The  drum-spindle  t  moves 
in  the  conical  spur-bed  B  and  in  the  flexible  collar-bed 
K.  The  construction  of  the  lower  spherical  spur-bed 
is  delineated  by  Fig.  15.  The  lower  end  of  the  spin- 
dle has  a  conical  groove,  into  which  a  pin  of  hard 
metal  (alloy  of  antimony)  is  placed.  This  is  the  so- 
called  spur-pin  upon  whose  lower  end  the  spindle  rests 
and  rotates  as  its  bearing,  which  is  made  of  the  same 
hard  alloy  of  antimony  as  is  used  for  the  spur-bed. 

The  friction  surface  of  the  pin  and  metal  bearing  is 
about  2.5  to  3.5  centimeters  (.{>S  to  1.38  inches)  in 
diameter,  and  is  shaped  at  present  entirely  even,  and 
not  as  was  formerly  the  case  convex  upon  concave  or 
convex  upon  convex.     Inasmuch  as  the 
entire  weight  of  the  shaft  and  drum  con- 
centrates on  this  friction  surface  and  the 
velocity  of  revolution  is  great,  the  fric- 
tion  is   certainly   very   strong,  and   fre- 
quently wears  out,  or  runs  the  shaft  ob- 

Lower  spheri-       . 

cai  step-bearing,  liquely.  However,  from  two  to  three  such 
metal-bearings  and  pins  for  every  appa- 
ratus will  do  the  service  for  each  season.  The  entire 
exterior  bed,  having  the  shape  of  a  cup,  rests  with  its 
upper  spherical  exterior  surface  in  the  disk-shaped 
cavity  of  a  second  bed,  the  latter  being  fastened  by 
screws  to  the  foundation-plate  6r,  and  hence  will  yield 


THE  TECHNOLOGY  OF  STARCH.         69 

at  once  to  any  pressure  of  the  shaft,  and  place  itself 
accurately  in  the  direction  which  the  latter  may 
assume  while  in  rotation. 

The  elastic  movable  star  "buffer-bed  K  (Figs.  15 
and  16),  is  connected  by  the  gum  buffer-rod  m  m  m 
with  the  head  plate  0  of  the  frame,  and  is  so  con- 
structed as  to  be  easily  movable  and  elastic,  causing 
the  shaft  by  means  of  its  pressure,  while  rotating,  .to 
run  obliquely  in  every  direction.  But  after  the  pres- 
sure has  ceased,  it  is  always  pushed  back  into  its 
vortical,  central  position.  In  case  of  an  unequal  dis- 
tribution of  the  contents  of  the  drum,  it  is  thus 
enabled,  by  dint  of  this  elastically  constructed  star 
buffer-bed,  to  revolve  around  its  own  axis.  On  ac- 
count of  this  elastic  pliancy,  Fesca's  centrifugal  ma- 
chine insures  in  a  high  degree  protection  against  the 
dangerous  results  of  an  unequal  loading. 

The  foundation-plate  O  connected  by  three  columns 
with  the  head-piece  0  forms  the  strong  framework 
of  the  centrifugal  machine.  This  foundation-plate 
is  screwed  with  its  four  eyes  aaaa,  and  small  gum- 
washers  on  a  wooden  bed-plate ;  this  latter,  however, 
rests  loosely  on  the  flooring  and  without  any  connec- 
tion with  the  same.  The  framework  of  the  machine  is 
thereby  completely  isolated  from  the  flooring,  and 
thus  the  shaking  which  it  suffers  by  the  rapid  rotation 
of  the  drum  is  so  completely  taken  up,  that  such  an 
apparatus  may  be  set  up  in  any  story,  without  fear  of 
any  shaking  of  the  building. 

The  driving  shaft  j»,  with  fast  and  loose  pulleys  rr', 
moves  in  both  beds^'y  of  the  frame  P.  Thfs  frame 
is  fastened  with  screws  to  its  foundation-plate  G  by 
four  slits  &  &,  in  such  a  manner,  that  it  may  be  moved 
upon  the  former,  the  distance  of  several  centimetres 


70  MANUFACTURE    OF    STARCH,    ETC. 

(1  cm.  —  .394  inch),  whereby  the  half-crossed  driving- 
belts  L  may  be  brought  to  assist  the  tension,  in  case 
they  have  by  long  use  stretched  somewhat.  The  belt 
L  drives  the  pulley  and  brake-dish  s /  v  is  the  handle 
of  the  double  brake,  which  catches  with  two  wooden 
blocks  v'  v'  against  the  lower  rim  of  the  disk  s,  in 
order  to  arrest  the  motion  of  the  machine  after  the 
completion  of  the  work.  The  engaging  and  dis- 
engaging gear  A.  is  situated  on  the  end  of  the 
"  machine,"  and  from  thence  several  of  these  machines 
may  be  attended  to  by  one  and  the  same  person.  8  is 
the  mantel  or  shield-drum,  which  collects  the  ejected 
water  that  is  flowing  off  by  S'.  The  charging  of  the 
"machine"  is  accomplished  by  the  so-called  paste- 
coach,  a  vessel  holding  exactly  the  quantity  that  is 
needed  for  every  drum,  and  which  is  carried  over  the 
apparatus  and  by  means  of  a  draw  emptied  into  the 
rotating  drum.  The  velocity  of  such  a  centrifugal 
machine  is  equal  to  from  1000  to  1200  revolutions  per 
minute. 

Finally,  it  maybe  mentioned,  that  the  so-called  cen- 
trifugal machine  of  Seele,  as  well  as  some  other  cen- 
trifugal machines  of  French  and  English  construction, 
has  its  peculiar  merits,  but  for  ail  practical  purposes 
that  of  Fesca  as  described  above  is  preferable. 

The  apparatus  known  as  "  Stele's  centrifugal"  is  -a 
most  excellent  piece  of  mechanism.  The  drum  is 
placed  by  means  of  a  spring  which  catches  into  the 
corresponding  notch  of  the  shaft  b  of '  the  centrifugal 
apparatus,  and  is  fastened  above  by  a  female  screw 
(nut)  to  the  point  of  the  cone  cc.  The  ring  affixed 
to  this  nut  serves  for  the  purpose  of  attaching  a 
tackle  of  pulleys,  by  the  aid  of  which  the  drum  and 
shaft  can  be  easily  lifted  out  of  the  casing  and  bed. 


TI1E    TECHNOLOGY    OF    STATCCH. 


71 


The  jacket  ee  is  made  of  thin  iron  plate  and  fastened 
upon  a  cast-iron  bottom,  whose  inclined  plane  causes 
the  hurled-out  water  to  flow  off  by/.  This  lower 
bottom,  on  which  the  buffer-bedding  I  is  also  fastened, 

Fig.  18. 


Centrifugal  drying-machine  (Seele's  construction). 

is  borne  by  three  iron  columns  g g,  and  screwed  to  the 
cast-iron  ground-plates  ii.  The  foundation  is  formed 
of  strong  oaken  joists.  The  construction  of  the  lower 
brasses  as  well  as  the  buffer-beds  is  similar  to  the  con- 
struction of  Fesca's  apparatus. 

Tlie  Bleaching  of  Starch. — Fn  addition  to  the  me- 
chanical operations  requisite  for  purifying  starch,  we 
will  now  make  some  observations  respecting  the  bleach-^ 
ing  of  starch.  In  many  establishments  for  the  maim- 


72  MANUFACTURE    OF    STARCH,    ETC. 

facture  of  potato  starch,  sulphuric  acid  is  applied,  in 
order  to  impart  to  the  starch  a  better  appearance, 
although  the  manufacturers  do  not  generally  admit 
this,  fearing  that  starch  thus  treated  may  not  find  con- 
sumers. There  are  even  cases,  where  it  becomes 
absolutely  necessary  to  apply  sulphuric  acid  for  pro- 
ducing a  white  starch,  as  for  instance  in  treating 
decayed  potatoes  or  those  affected  with  the  "rot,"  or 
wet  starch  in  which  the  fruit  sap  has  commenced  to 
decompose.  In  order  not  to  leave  in  the  starch  any 
trace  of  latent  sulphuric  acid,  by  which  it  would  be 
chemically  changed  (dextrine  and  glucose)  and  become 
thereby  useless  for  many  purposes,  a  small  portion  of 
ammonia  should  be  added  to  the  washing  water.  When- 
ever sulphuric  acid  has  been  made  use  of,  it  will  also 
answer  the  purpose  to  neutralize  the  same  by  applying 
small  quantities  of  milk  of  lime,  in  any  case  where 
ammonia  should  be  deemed  inadvisable.  On  the  other 
hand,  the  application  of  fixed  caustic  alkalies  is  not 
expedient,  since  the  starch  combined  therewith  will 
swell  up  to  a  paste  and  even  when  used  in  smaller 
portions  will  become  slimy,  causing  the  process  of 
washing  to  become  still  more  difficult.  Chlorides  are 
also  much  used  for  the  bleaching  of  starch.  Thus 
already  as  early  as  1821,  a  patent  was  issued  in  Eng- 
land to  M.  Hall,  for  extracting  the  j^ellow  pigment 
from  starch,  by  which  the  starched  linen  is  rendered 
yellowish,  and  hence  necessitating  the  treatment  of 
the  same  with  blue  coloring  matter  (blueing).  This 
bleaching  consists  in  mixing  the  starch  with  water, 
after  it  has  been  finished  to  the  cake  formation,  and 
afterwards  diluting  the  starch  to  the  thickness  of 
cream,  and  adding  8  litres  of  the  so-called  "bleaching 
fluid"  for  each  kilogramme  (2.2  Ibs.)  of  starch.  This 


THE  TECHNOLOGY  OF  STARCH.         73 

bleaching  fluid  is  composed  of  70  grammes  (2.45  ozs. 
avd.)  of  chloride  of  lime  dissolved  in  4  litres  (8.4 
pints)  of  water.  After  a  thorough  mixing,  8  litres 
(16.8  pints)  of  water  are  added,  and  the  liquid  is  left 
to  settle,  in  order  to  cause  the  indissoluble  parts  to 
precipitate.  To  this  strained-off  liquid  140  grammes 
(4.9  ozs.  avd.)  of  sulphuric  acid  diluted  by  8  litres 
(1G.8  pints)  of  water  are  added  and  well  stirred  in  order 
to  cause  the  acid  to  dissolve  all  the  heterogenous  in- 
gredients, and  in  the  solution  thus  obtained  8  litres 
of  water  are  poured  for  each  kilogramme  (2.2  Ibs.) 
of  starch.  This  fluid  is  then  permitted  to  settle 
sufficiently,  to  allow  the  starch  thus  bleached  and 
refined  to  precipitate.  Thereupon  the  precipitated 
starch  is  washed  out  with  a  sufficient  quantity  of  water 
to  free  the  same  from  all  chloride  and  acid,  and  then 
dried  in  the  usual  way.  Starch  bleached  by  this 
method  is  remarkably  white,  and  all  laces  and  textiles 
starched  therewith  attain  a  whiteness  and  lustre  which 
common  starch  cannot  impart. 

Starch  may  likewise  be  bleached  by  applying  the 
so-called  "bleaching  water"  of  Leuchs,  which  is  also  a 
solution  of  chloride  of  lime  in  water,  to  which  some  sul- 
phuric acid  has  been  added.  Another  means  of  bleaching 
starch,  which  finds  much  application  in  the  manufacture 
of  wheat  starch,  is  the  use  of  sal  ammoniac.  For  the 
extraction  of  the  empyreuma  (fusel  oil)  from  potato 
starch,  of  course  in  smaller  quantities,  alcohol  is  most 
profitably  employed. 

The  Drying  Process. — As  the  manufacture  of  potato 
starch,  according  to  the  nature  of  the  material  from 
which  it  is  obtained,  is  generally  the  work  for  that 
season  that  intervenes  between  the  autumn  and  the 
spring,  it  is  necessary  that  heated  rooms  with  good 


74  MANUFACTURE    OF    STARCH,    ETC. 

ventilation,  that  is,  with  egress  for  damp  air  and  in- 
gress for  dry  air,  be  constructed.  Such  rooms  are 
termed  drying  chambers.  For  this  reason  alone  a 
steam  engine  is  required  for  the  needed  manipulations, 
for  instance  as  a  motive  power  for  the  washing  drum, 
the  grater  and  the  sifting  apparatus,  etc.,  and  the 
exhaust  steam  may  be  utilized  for  heating  the  drying- 
rooms.  In  this  drying-room  frames  are  placed  for 
hurdles,  on  which  the  damp  starch  is  spread  for  dry- 
ing. The  starch,  as  it  is  obtained  by  the  last  washing 
from  the  depositing  vats,  or  by  the  operation  on  the 
inclined  plane,  is  altogether  too  damp  to  permit  of  an 
immediate  transfer  to  the  drying-room.  It  forms  in 
this  state  a  very  dense  dough,  which  usually  still  con- 
tains 66  per  cent,  of  its  weight  of  water.  A  part  of 
this  water  must  be  previously  removed,  and  this  may 
be  accomplished  in  various  ways;  for  instance  by  re- 
peatedly ^placing  dry  cloths  over  the  wet  and  spongy 
mass,  until  these  cloths  cease  to  absorb  water,  or  by 
using  porous  stones  (bricks  or  gypsum  slabs)  as  ab- 
sorbents. As  soon  as  the  starch  has  lost  its  spongy 
appearance  it  is  dug  out  with  a  spade  and  spread  over 
the  hurdles  in  the  dry  ing-room.  The  method  of  press- 
ing out  the  water  from  the  starch  becomes  only  prac- 
ticable when  but  thin  layers  of  starch  are  placed  under 
the  press,  because  in  the  case  of  thicker  layers  the 
mass  will  remain  wet  and  spong}7  inside.  The  air- 
pump  too  may  be  used  for  this  purpose. 

But  more  perfectly  and  expeditiously  can  this  drying 
process  be  accomplished,  by  means  of  the  centrifugal 
machine. 

The  construction  of  a  suitable  drying-room  is  deli- 
neated and  explained  as  follows  : — 

In  Fig.  19  a  drying-room    or   starch  kiln  as  con- 


THE    TECHNOLOGY    OF    STARCH. 


75 


s  true  ted  by  Lacambre  and  Persac  is  represented.  This 
room,  on  account  of  its  convenience  and  ingenious 
arrangements,  is  not  only  used  in  starch  manufactories, 
but  also  in  breweries  for  the  drying  of  malt.  The  dry- 
ing apparatus,  wherein  the  starch  is  gradually  exposed 
to  a  temperature  of  from  25°  to  100°  C.  (77°  to  212°  F.), 
consists  of  a  large  vaulted  apartment,  corresponding 
to  the  capacity  of  the  establishment.  The  heating 
apparatus  is  placed  below  the  drying-room. 

Fig  19. 


Lacambre's  and  Persac's  drying-room. 

The  latter  consists  of  a  large  furnace  A,  which  is 
heated  by  A'  and  from  whence  the  heated  articles  for 
combustion  circulate  through  the  iron  pipes  bed  efg 
h  ij,  and  finally  after  having  parted  with  the  greater 
portion  of  their  heat  and  ceased  to  do  so,  escape  by  i 
and  j  through  the  chimney.  The  outer  air  enters 


76  MANUFACTURE   OF    STAKCH,   ETC. 

through  the  apertures  in  the  floors,  becoming  warm  by 
being  brought  into  contact  with  the  heating  pipes  it 
escapes  through  the  opening  D  into  the  drying-room, 
where  it  gradually  passes  in  the  direction  of  the  darts 
over  the  inclined  surfaces  (7,  C\  C\C\  O\  <75,  (73and 
C\  finally  escapes  through  the  apertures  <78,  (79,  and  (710, 
being  then  loaded  with  moisture.  The  starch  is  moved 
in  an  opposite  direction.  It  is  put  in  through  the  gate 
B*  and  spread  on  the  inclined  plane  (?7,  and  after 
having  remained  there  for  some  time  is  shovelled  upon 
the  table  (76,  and  at  once  drawn  from  the  corresponding 
gates  JB\  B*,  JB\  and  B  until  it  arrives  below — near 
(7 — in  a  perfectly  dry  state,  when  it  is  finally  emptied 
over  cl  through  the  gate  B,  into  the  bags  S,  Sl.  Such 
a  drying  apparatus  works  continuously,  so  that  as  soon 
as  the  first  part  of  the  starch  has  been  removed  from 
the  upper  tables  (77,  a  fresh  supply  of  moist  starch  is 
placed  thereon.  Thus,  every  time  the  dry  product  is 
withdrawn  near  C\  the  starch  is  scooped  off  from  all 
the  tables,  viz.,  (71,  (72,  C\  etc.,  across  each  inclined 
plane,  while  the  uppermost  table  is  filled  with  fresh 
starch. 

TJie  Yield  of  Starch  from  Potatoes  and  their  Pulp. 
— No  grating  apparatus  is  able  to  open  all  the  cells  of 
the  potato  substance;  hence,  the  entire  amount  of 
starch  is  never  obtained  by  the  manufacturer.  The 
yield  of  starch  amounts  to  but  66  to  75  per  cent,  of 
the  starch  contained  in  the  potatoes,  when  the  opera- 
tion is  performed  in  a  rational  way.  The  maximum 
yield  was  attained  by  Fesca  with  his  grater  and  im- 
proved cylinder-sieve.  100  kilogrammes  (220  Ibs.)  of 
potatoes  of  19  per  cent,  of  perfectly  dry  starch  (  — 
23.17  per  cent,  air-dried  starch)  furnished  him  17.5 
kilogrammes  (38.5  Ibs.)  of  air-dried  starch ;  thus  572 


THE  TECHNOLOGY  OF  STAKCH.          77 

kilogrammes  (1258  Ibs.)  of  potatoes  yielded  103  kilo- 
grammes (220  Ibs.)  of  air-dried  starch.  By  carrying 
on  this  business  on  a  larger  scale,  6|  hectolitres  (18.2 
bushels)  of  potatoes  (about  600  kilogrammes,  or  1320 
Ibs.)  were  used  for  obtaining  100  kilogrammes  (220 
Ibs.  of  air-dry  starch,  which  corresponds  closely 
enough  with  our  statement. 

The  Manufacture  of  Potato-flour. — Potato-flour  is 
the  name  given  to  the  dried  and  ground  potato  sub- 
stance after  having  been  lixiviated  in  water,  dried  and 
ground,  and  hence  is  a  mixture  of  starch  and  cellulose. 
Potato-flour  when  properly  manufactured  is  entirely 
white,  and  can,  with  regard  to  its  external  appearance, 
scarcely  be  distinguished  from  potato-starch.  It  con- 
tains from  8  to  10  per  cent,  of  albuminous  substances,* 
and  for  this  reason  approaches,  as  to  its  composition, 
the  flour  obtained  from  cereals.  At  all  events,  potato- 

*  The  albuminous  compounds  comprise  a  series  of  constituents 
of  primary  importance  in  histogenesis,  or  the  formation  of  tissue, 
as  the'  tissue  of  all  natural  forms,  vegetable  no  less  than  animal, 
is  largely  composed  of  albumen.  Albumen,  the  nominal,  is  also  the 
actual  base  of  this  group,  with  which  we  find  casein,  globulin,  and 
fibrin — these  are  what  are  called  "protein  compounds,"  a  name  first 
applied  to  them  under  a  mistaken  notion  that  they  contained  a  cer- 
tain organic  base,  free  from  sulphur  and  phosphorus,  which  was 
called  protein.  These  compounds  cannot  be  resolved  by  analysis, 
like  complex  inorganic  matter,  into  two  or  more  compounds  that 
may  be  resynthesized  into  their  original;  and  therefore  no  exact  clue 
has  been  obtained  to  their  very  complex  composition.  The  protein 
compounds  are,  however,  extremely  susceptible  to  the  influence  of 
the  air  at  ordinary  temperatures,  decomposing  spontaneously  with 
great  rapidity ;  this  decomposition  ultimateljr  resolves  them,  with 
oxygen  from  the  atmosphere,  into  water,  carbonic  acid,  and  am- 
monia, and  various  organic  compounds  may  be  formed  by  a  less 
complete  disintegration. 

Of  all  the  protein  compounds,  albumen  is  the  special  pabulum 


78  MANUFACTURE    OF    STARCH,    ETC. 

flour  deserves  mention  here  as  an  excellent  means  of 
nutrition.  This  branch  of  industry,  however,  being 
still  in  its  infancy,  has  hitherto  been  more  especially 
cultivated  in  France,  and  forms  a  great  article  of  ex- 
port to  England,  where  it  is  principally  used  for  pro- 
viding emigrant  vessels  with  a  cheap  and  wholesome 
food.  Potato-flour  is  also  used  occasionally  in  lieu  of 
grain  flour  for  bread  baking,  for  preparing  soups,  and 
as  an  admixture  for  chocolate. 

THE  MANUFACTURE  OF  WHEAT  STARCH. 

The  Raw  Material. — The  ripe  grain  of  wheat  forms 
a  cylindrical  shaped,  on  both  ends  rounded  off  body, 
which  on  one  of  its  sides  is  deeply  furrowed  through- 
out its  length.  The  outer  cover  of  this  body  is — 
more  especially  upon  one  of  its  ends — covered  with 
numerous  fine  hairs.  "While  these  hairs  cling  to  the 
spurs  of  fungi,  which  come  in  contact  with  them,  they 
cause  under  certain  conditions  injury  to  the  grain. 
The  specific  gravity  of  the  wheat  grain  ranges  ac- 
cording to  its  quality  from  1  32  to  1.60;  the  absolute 
weight  of  100  wheat  grains  varies  from  1.8  to  6.5 
grammes  (27.77  to  100  grains),  which  furnishes  a 

(nutriment)  of  the  tissues.  According  to  Mulder  albumen  is  com- 
posed as  follows: — 

Carbon 53.5  per  cent. 

Oxygen 22.0 

Hydrogen         .        .        .        .        .        .         .       7.0        " 

Nitrogen 15.5 

Sulphur .       1.6        " 

Phosphorus .0.4        " 

Professor  Liebig  denies  the  presence  of  phosphorus  as  a  consti- 
tuent, and  claims  that  it  has  no  existence  in  any  article  of  food,  or 
in  any  tissue  of  the  body,  except  in  combination  as  phosphoric  acid. 


THE  TECHNOLOGY  OF  STARCH.          79 

difference  in  the  size  of  the  grains  of  from  1  to  3.6. 
The  weight  of  1  hectolitre  (2.8  bushels)  of  wheat  is 
calculated  on  an  average  at  75  kilogrammes  (165  Ibs.), 
but  varies  according  to  its  quality  from  70  to  82  kilo- 
grammes (154  to  180  Ibs.).  The  number  of  the  various 
species  of  wheat  in  a  wider  sense,  i.  e.,  the  different 
varieties  caused  by  degeneration,- is  already  very  large, 
and  yearly  increased,  by  new  methods  of  cultivation. 
Scientific  men  classify  wheat  in  seven  distinct  varie- 
ties, but  in  industrial  practice,  wheat  is  classified  as 
to  its  degrees  of  hardness,  into  three  different  kinds, 
to  wit: — 

Hard,  Glassy,  or  Steel-like  Wheat,  with  a  heavy,  dense, 
somewhat  transparent,  reddish  grain.  This  wheat  is 
least  hygroscopic,  rich  in  albumen,  fat,  and  alkalies, 
and  yields  but  little  bran  when  ground;  but  the  flour 
thereof  is  not  very  white. 

Soft  or  White  Wheat,  with  a  soft,  white,  not  transparent 
grain  ;  contains  less  gluten,  fat,  and  alkalies  than  the 
first  kind,  and  can  be  ground  with  ease,  furnishing  a 
beautiful  white  shining  flour. 

Semi-hard  or  Medium  Soft  Wheat. — This  variety 
holds  the  middle  ground  (as  to  its  properties)  between 
the  first  two  named  kinds,  without  possessing  exactly 
the  properties  of  the  one  or  the  other.  It  is  especially 
valued  for  the  manufacture  of  flour,  on  account  of  the 
ease  with  which  it  separates  from  the  bran,  and  further- 
more because  the  grit  of  this  sort  furnishes  a  beautiful 
white  flour.  The  hard  and  soft  varieties  of  wheat  are 
easily  discernible,  by  close  observation  of  the  grain, 
when  bitten  in  two  with  the  teeth  or  by  bruising  the 
same  lightly  with  a  hammer.  Hard  wheat  has  inside 
a  horny  and  glassy  appearance,  like  joiner's  glue, 
having  likewise  its  yellow  color.  Soft  wheat,  on  the 


80  MANUFACTURE   OF    STARCH,    ETC. 

other  hand,  has  a  mealy  appearance,  and  is  very  tender 
and  white  inside.  The  former  is  not  easily  pene- 
trated by  water;  the  latter,  however,  is  very  easily 
penetrated.  The  physical,  very  sharply  characterized 
peculiarities  do  not  admit  of  an  easy  confounding  of 
these  two  varieties  of  wheat.  The  harder  kinds,  as  a 
rule,  contain  more  gluten  and  less  starch  than  the 
softer  sorts,  and  are  therefore  more  suitable  for  baker's 
use  than  for  the  manufacture  of  starch. 

Of  the  soft  species,  there  are  furthermore  two  other 
groups,  which  the  manufacturer  of  starch  should  know, 
i.  e.,  the  red  and  the  white  wheat,  which  have  been 
thus  designated  by  their  much  varying  color.  Each 
of  these  kinds  has  its  peculiar  value  for  the  production 
of  starch.  Inasmuch  as  the  red  wheat  is  generally 
harder,  and  hence  contains  comparatively  more  gluten 
and  less  starch,  and  besides  is  more  expensive  than  the 
white  wheat,  the  manufacturer  of  starch  prefers  the 
white  and  soft  wheat  for  his  use,  which  in  every  respect 
is  best  suited  for  producing  starch. 

The  inner  structure  of  the  wheat-grains  is  best  dis- 
cerned by  cutting  one  of  them  open  and  subjecting 
it  to  the  magnifying  power  of  a  microscope.  Such 
a  grain  is  composed  of  three  essentially  different 
strata  laying  above  each  other,  viz.,  the  grain-shell, 
the  gluten  layer,  and  the  flour  body.  The  outer  hull 
or  shell  is  essentially  composed  of  fibrin  (cellulose  or 
cellular  substance),  being  indissoluble  by  ordinary 
solutions,  especially  so  by  water,  and  hence  is  in  the 
manufacture  of  starch  without  any  significance.  In 
consequence  of  this  indissoi ability  it  acts  in  preserving 
the  substances  enveloped  therein.  The  weight  of  the 
hull  amounts  usually  to  from  4|  to  7  per  cent.;  it, 
however,  increases  at  times  to  15  per  cent.  Imme- 


THE    TECHNOLOGY    OF    STARCH.  81 

diately  adjacent  to  the  hull  is  situated  the  gluten  layer, 
i.  e.y  that  part  of  the  grain  which  contains  the  greatest 
portion  of  gluten.  1<  inally  we  notice  on  the  end  of 
the  grain  immediately  under  the  gluten  cover,  the 
germ,  enveloped  by  the  gluten  layer.  The  germ  is 
that  part  of  the  seed  or  grain  by  which  the  plant  is 
developed,  the  embryo.  It  is  impregnated  by  fatty 
oils,  and  when  pressed  upon  paper  causes  a  fatty  stain. 
These  contents  of  fatty  oil  secure  to  it  the  power  to 
withstand  the  softening  and  destructive  influences  of 
dampness.  The  mealy  part  of  the  grain  furnishes 
when  ground  the  flour,  while  the  shell  and  the  germ 
on  account  of  their  greater  toughness  become  less 
perfectly  broken  np  and  form  the  bran.  In  the  mealy 
body  two  organic  substances  predominate:  the  starch 
and  the  gluten;  besides  these  are  found  gum,  a  small 
quantity  of  albumen,  and  of  so-called  extractive  sub- 
stances, i.  e.,  of  substances  whose  nature  is  not  yet 
accurately  known,  also  various  salts,  which  are  prin- 
cipally phosphatic. 

The  amount  of  water  in  the  air-dried  wheat  grains 
fluctuates  on  an  average  between  11  and  16  per  cent., 
and  depends  solely  on  the  relative  dampness  of  the 
atmosphere.  Respecting  the  increase  of  the  size  of  the 
grain  by  the  increase  of  the  amount  of  moisture,  it  has 
been  found  that  wheat  grains  moistened  with  15  per 
cent,  of  water  increase  from  30  to  31  per  cent,  in 
volume,  so  that  for  this  reason  to  the  grain  dealers  a 
high  state  of  moisture  is  of  greater  advantage  for 
measuring  than  for  weighing. 

The  amount  of  starch  in  wheat  varies  from  50  to  75 
per  cent,  of  the  weight  of  the  whole. 

The  quantity  of  gluten  in  wheat  is  also  very  fluc- 
tuating, and  as  a  rule  is  generally  large,  where  the 


82  MANUFACTURE    OF    STARCH,    ETC. 

contents  of  starch  are  small.  In  general  it  varies 
from  10  to  35  per  cent,  of  the  weight  of  the  wheat. 

The  amount  of  gum'  in  the  grain  of  wheat  is  usually 
1|  to  2|  per  cent.;  in  some  cases  it  is  as  high  as  from 
5  to  6  per  cent.* 

The  amount  of  alkalies  (ashy  substances)  varies  in 
wheat  in  maximum  \  per  cent. 

The  amount  of  water  (in  air-dry  condition)  varies 
between  11  and  16  per  cent.,  of  which,  however,  on 
account  of  the  drying  of  the  wheat  in  a  temperature 
of  37.5°  C.  (99.5°  F.),  but  about  4  per  cent,  evaporates 
while  the  remainder  escapes  only  at  an  increased 
temperature. 

Respecting  the  chemical  composition  of  wheat, 
numerous  analyses  have  been  made.  The  Value  of 
American  wheat  according  to  its  contents  of  starch  and 
gluten  is  as  follows: — 


Species  of  wheat  from  — 

1000  weight  parts  of  wheat 
contain  — 

Starch. 

Gluten. 

New  York  State      

519.6 
517  4 

229.7 
235.4 
260.1 
302.6 
329.5 

Virginia  
Virginia  
Philadelphia    

480.4 
438.6 

448.7 

As  to  its  appearances  compared  with  potato  starch, 
wheat  starch  differs  not  only  in  form  and  structure, 
but  also  in  this  respect:  that  the  granules  of  wheat 
starch  are  always  smaller,  hence  are  deposited  in  water 
much  slower.  For  the  same  reason,  the  air-dried  wheat 
starch  is  less  transparent,  of  a  dull  white.  In  the  air- 
dried  state  it  contains  12  per  cent,  of  moisture,  that  is, 
less  than  potato  starch.  For  the  purpose  of  manu- 

*  Its  contents  of  albumen  vary  from  \  to  1^  per  cent. — HUTTER. 


THE  TECHNOLOGY  OF  STARCH.          83 

fact u ring  wheat  starch  it  is  of  importance  to  know 
that  a  part  of  the  starch  contained  in  the  wheat  is  in  a 
very  close  mechanical  combination  with  the  gluten. 
This  glutinous  starch  appears  in  every  method  of 
manufacturing  starch  from  wheat,  and  occasions  a  loss 
of  pure  starch,  since  the  separation  of  starch  from  the 
gluten  is  not  perfectly  attainable;  because  the  "glu- 
tinous starch"  is  probably  a  compound  of  the  unripe 
starch  substance  with  gluten.  From  wheat-flour  this 
gluten  starch  is  obtained  in  by  far  larger  quantities, 
presumably  on  account  of  the  total  tearing  of  many 
covers  of  starch-granules  during  the  process  of  grinding, 
when  the  inner  substance  of  these  granules  adheres 
firmly  to  the  gluten.  Wheat  which  has  been  affected 
by  mildew  shows  in  most  cases  such  a  decrease  in 
the  contents  of  starch,  that  the  working  up  of  such 
wheat  would  be  unprofitable.  Wheat  not  entirely  ripe 
yields  an  inferior  amount  of  starch.  "Wheat  when 
beginning  to  sprout,  according  to  the  state  of  its  ger- 
mination, produces  from  6  to  30  per  cent,  less  starch 
than  a  good  quality  of  wheat. 

The  Production  of  Starch  from  Wheat. — In  all  manu- 
factories for  the  production  of  starch  from  potatoes — 
as  we  have  already  seen — the  separation  of  the  starch 
is  essentially  brought  about  in  the  same  manner:  the 
potatoes  are  grated  or  ground,  and  from  the  paste  the 
starch  is  washed  out,  and  only  the  mechanical  appli- 
ances for  the  various  operations  differ.  The  manu- 
facture of  starch  from  wheat  is  in  this  respect  quite 
different.  In  this  the  method  of  separating  the  starch 
is  not  always  the  same,  and  there  are  various  methods 
of  manufacturing  it.  The  reason  for  this  will  become 
clear  by  the  following:  In  wheat,  substances  are  con- 
tained, besides  the  starch,  having  great  value  as  nutri- 


84  MANUFACTURE    OF    STARCH,    ETC. 

ments,  of  which  we  would  mention  the  gluten.  The 
separation  of  starch  from  wheat  may  be  done  so  that  a 
large  part  of  the  gluten  may  he  saved  as  a  subordinate 
product,  but  this  process  may  also  be  manipulated  in 
such  a  way  that  the  greater  part  of  this  substance  is 
lost.  If  the  former  or  the  latter  method  did  not  differ 
with  regard  to  the  ease  and  completeness  of  separating 
and  refining  the  starch,  the  choice  of  the  method  would 
not  be  doubtful,  as  then  only  the  first  would  be  chosen. 
Such  a  difference,  however,  does  take  place,  since  the 
simultaneous  gaining  of  the  gluten  complicates  the 
complete  separating  and  refining  of  the  starch.  In- 
dividual (local)  conditions,  therefore,  must  decide  the 
choice,  and  wherever  the  gluten  can  be  disposed  of 
profitably,  it  will  be  saved;  if,  on  the  other  hand,  this 
becomes  impossible,  then  it  is  allowed  to  be  wasted. 
It  is  self-evident  that  the  loss  of  a  substance  for  food 
like  this  is  always  to  be  regretted;  and  it  should  there- 
fore be  the  endeavor  to  perfect  the  manufacture  of 
starch  from  wheat  in  such  a  manner  as  to  utilize  the 
gluten,  which  is  obtained  simultaneously  during  the 
operation.  Before  proceeding  with  the  elucidation  of 
the  various  methods,  they  should  be  previously  charac- 
terized by  a  few  lines. 

^According  to  the  oldest  method  which  is  still  in 
vogue,  the  wheat  is  swelled  by  water  until  it  becomes 
soft,  and  it  is  then  bruised.  This  bruised  mass,  diluted 
in  water,  is  left  to  settle  for  several  days;  it  ferments, 
becomes  very  acid,  and  of  bad  smell  (putrefies).  The 
tough  gluten,  which  hinders  the  separation  of  the 
starch,  is  partly  dissolved  by  the  acid,  and  partly  dis- 
aggregated, and  loses  some  of  its  toughness;  from 
the  fermented  substance  the  starch  can  be  easily  and 
very  fully  separated.  A  modification  of  this  method 


THE  TECHNOLOGY  OF  STARCH.          85 

consists  in  the  rough  grinding  or  bruising  of  the 
wheat,  soaking  the  same  in  water,  and  allowing  it  to 
ferment  By  this  oldest  method,  the  hulls  of  the 
wheat  as  well  as  a  small  portion  of  its  gluten  (at  most 
but  one  quarter)  are  obtained  in  a  sour  state,  and  thus 
form  a  food  only  fit  for  hogs. 

According  to  the  second  method,  starch  is  made  of 
the  swelled  and  bruised  wheat  at  once,  without  sub- 
jecting it  to  the  process  of  fermentation,  in  which  case 
sweet  gluten  and  hulls  form  a  residuum. 

According  to  a  third  method,  flour  is  produced  from 
the  wheat,  so  that  bran  is  obtained  as  a  valuable  aux- 
iliary product  from  the  flour,  the  starch  is  separated, 
and  sweet  gluten  also  remains  as  a  residuum. 

We  therefore  distinguish — 

A.  The  older  method  (by  acidulous  fermentation), 
a,  from  wheat  not  ground  or  bruised ; 

&,  from  bruised  wheat. 

B.  The  more  modern  method  (without  fermen- 

tation). 

(7.  Martin's  method,  consisting  in  the  manipula- 
tion of  wheat  in  its  milled  (ground)  state 
(flour). 

The  oldest  method  is  still  more  generally  in  use  for 
the  manufacture  of  starch,  and  we  therefore  begin  with 
its  explanation. 

A.  Method  of  Acetous  Fermentation. — The  fabrica- 
tion of  wheat  starch  by  the  process  of  sour  (acetous) 
fermentation,  has  been  carried  on  from  a  very  early 
period,  and  is  at  present  still  in  vogue  in  many  estab- 
lishments. In  countries  where  the  milling  of  flour  is 
subject  to  the  burden  of  taxation,  it  is  the  only  method 
advisable. 

This  method,  however,  brings  forth  a  S3ries  of  in- 


86  MANUFACTURE    OF    STARCH,    ETC. 

conveniences,  as  by  far  the  greater  part  of  the  gluten, 
serving  as  nourishment  for  man  and  food  for  our  do- 
mestic animals,  is  thereby  lost,  and  the  putrefied  odors 
of  the  establishments  endanger  the  health  of  the  neigh- 
borhood, and  it  pollutes  the  streams  into  which  the 
waste  flows,  causing  a  most  disagreeable  smell ;  hence, 
those  establishments  in  which  wheat-starch  is  made 
according  to  the  old  method,  are  to  be  counted  among 
those  injurious  to  health. 

The  manufacture  of  starch  by  this  older  method  is 
divided  into  the  following  operations  : — 

a.  The  steeping  and  crushing  (bruising)  of  the 
wheat ; 

&.  Fermenting  of  the  bruised  wheat; 

c.  The  separating  of  the  starch  from  the  fermented 
substance ; 

d.  The  refining  of  the  raw  starch; 

e.  The  drying  of  the  starch. 

a.  TJie  Steeping  and  Bruising  of  the  Wheat. — The 
steeping  of  the  wheat  in  water  is  performed  in  the  so- 
called  steeping-troughs  or  cisterns.  The  purpose  of 
this  operation  is,  in  the  first  place,  to  soften  the  wheat, 
in  order  to  separate  the  starch  from  the  gluten  and 
the  hulls;  and, 'furthermore,  to  make  it  free  from  all 
impurities. 

The  steeping  troughs  are  prepared  of  wood,  iron, 
sandstone,  or  cement.  Those  made  of  stone  are  either 
of  large  sandstone  slabs  or  of  bricks,  joined  and 
cemented  with  mortar  lime  and  lined  with  cement. 
These  cisterns  are  termed  "  steeping -troughs"  The 
shape  may  be  either  round  or  square ;  but  of  more 
importance  than  the  form  is  the  suitable  location  of 
the  cistern  in  the  establishment,  as  it  is  necessary  that 
it  be  easily  supplied  with  water,  and  the  stagnant, 


*      THE  TECHNOLOGY  OF  STARCH.          87 

already-used  water  as  easily  drained  off.  It  should 
also  be  thought  of,  that  the  wheat  to  be  steeped  can  be 
directly  conducted  into  the  troughs  by  means  of  a 
gutter,  or  elevator,  etc.  The  locality  where  the  cis- 
terns are  placed  must  be  guarded  against  the  freezing 
of  the  water,  and  hence  should  be  supplied  with  a  heat- 
ing apparatus,  in  order  to  keep  up  its  temperature  in 
winter.  The  temperature  of  the  locality  for  steeping 
should  at  least  be  12°.5  to  15°  C.  (54°.o  to  59°  F.).  On 
the  bottom  of  the  steeping-trough  is  an  opening,  with 
a  spigot,  which  is  supplied  inside  with  a  sieve  of  cop- 
per-plate, in  order  to  prevent  the  flowing  oft'  of  the 
grain.  Besides  this,  the  bottom — near  the  wall — is 
supplied  with  a  valve,  which  serves  as  a  manhole  for 
the  suitable  empt}ring  of  the  cistern.  Through  this 
opening,  which  may  also  be  placed  on  one  of  the  sides 
of  the  trough,  immediately  above  the  bottom,  the  al- 
ready steeped  grain  is  despatched  to  undergo  the  further 
manipulation  of  bruising.  The  steeping  of  the  wheat, 
which  has  previously  been  cleansed  of  dust  and  other 
foreign  admixtures,  is  performed  as  follows:  The  cistern 
is  filled  to  one-half  of  its  capacity,  with  pure,  and  if  pos- 
sible soft  water,  one  part' of  the  wheat  placed  therein, 
and  by  the  aid  of  wooden  rakes  divided,  that  is,  diligently 
stirred  in  the  water.  The  hulls  floating  on  the  surface, 
the  empty  grains,  and  dross  are. skimmed  off  with  a 
sieve.  Thereupon  more  wheat  is  put  in,  and  the  same 
process  is  repeated.  After  the  entire  quantity  of  wheat 
has  been  placed  in  the  cistern,  so  much  water  is  poured 
in  as  will  cause  it  to  rise  to  the  height  of  from  5  to  8 
centimetres  (1.97  to  3.15  inches)  above  the  wheat,  and 
the  process  of  removing  hulls  and  dross  is  repeated. 
The  water  to  be  used  for  this  operation  must  be  pure. 
A  pure  well  water  is  just  as  suitable  as  pure  river 


88  MANUFACTURE    OF    STAHCH,    ETC.  « 

water,  and  must  have  a  temperature  of  at  least  10°  to 
12°.5  C.  (50°  to  54°.5  F.);  but  in  case  the  steeping  is 
to  be  hastened,  water  of  a  temperature  of  30°  to  38°  C. 
(86°  to  100°.4  F.)  may  be  used.  During  the  period  of 
this  steeping,  some  carbonic  acid  gas  is  generating, 
which  mostly  remains  absorbed  in  the  water.  The 
steeping  water  assumes  a  yellowish  color,  and  an  odor 
like  straw,  because  it  partly  dissolves  the  soluble  in- 
gredients of  the  hulls. 

The  wheat  absorbs  water  and  swells  up;  absorbing 
it  to  about  one-half  of  its  own  weight,  and  the  circum- 
ference of  the  grain  grows  more  than  one-fifth.  The 
quantity  of  the  extract,  which  the  water  has  drawn  from 
the  hull — the  color  of  which  becomes  usually  somewhat 
paler — amounts  to  scarcely  one-seventieth  of  the  weight 
of  the  wheat.  Gradually  the  wheat  softens  to  such  a 
degree  that  it  may  easily  be  crushed  between  the  fingers 
when  taken  by  both  ends  and  thus  pressed;  the  grains  are 
then  penetrated  by  the  water  into  the  very  innermost 
part  of  their  meal-nucleus.  The  time  which  is  required 
for  an  ample  steeping  depends  on  the  quality  of  the 
wheat  and  water,  but  more  especially  on  the  proper 
temperature  of  the  latter.  Wheat,  rich  in  starch,  of 
thin  hulls,  when  not  too  much  dried  out,  steeps  more 
easily  than  horny,  glutinous  older  wheat.  The  softer 
the  water,  and  the  higher  its  temperature  and  that  of 
the  locality  in  which  the  cisterns  are  placed,  the  sooner 
the  softening  process  will  take  place.  In  summer  four 
days  may  suffice,  while  during  the  winter  season  from 
ten  to  eleven  days  may  be  required. 

As  soon  as  the  requisite  degree  of  soaking  has  been 
attained,  the  entire  steeped  mass  is  well  stirred,  and 
the  stagnant  water  is  drawn  off,  and  for  this  purpose 
a  cock  connected  with  a  sieve  plate  has  been  affixed. 


THE  TECHNOLOGY  OF  STARCH.          89 

Thereupon  pure  water  is  again  conducted  into  the 
steeping-trough  in  order  to  rinse  off  the  still  remaining 
slime.  The  water  is  then  again  drained  out,  and  the 
grain  is  left  to  remain  in  the  cistern  several  hours 
longer.  Meantime  the  waste-pipe  cock  is  left  open  so 
that  the  water  may  completely  run  off;  whereupon  the 
wheat  is  withdrawn  through  the  manhole  and  taken  to 
the  crushing  mill.  The  steeping  apparatus  must  of 
course,  soon  after  it  has  been  emptied,  be  thoroughly 
cleaned  before  wheat  is  again  placed  therein.  During 
warm  weather,  sometimes  even  in  the  spring  and 
autumn,  it  may  happen  that  the  steeping  water  acquires 
an  acid  property  ere  yet  the  wheat  is  thoroughly 
steeped.  This  is  ascertained  by  the  peculiar  acid  taste 
of  the  steeping  water.  Water  thus  tainted  must  at 
once  be  removed  from  the  cistern  and  replaced  by 
fresh,  cold  water.  It  is  best  to  renew  the  water  twice 
or  even  three  times  during  the  process  of  steeping,  and 
moreover  this  should  be  done  oftener  during  the  com- 
mencement of  the  operation  than  later,  since  the  ex- 
tracted substances,  which  most  incline  the  water  to 
become  putrefied,  are  dissolved  in  larger  quantities  at 
the  commencement  of  the  steeping. 

After  the  end  of  the  steeping-process,  the  steeped 
wheat  is  placed  upon  the  so-called  Bruising  Mill  or 
Grain  Crusher.  Such  an  apparatus  is  represented  by 
Fig.  20. 

This  apparatus  consists  of  two  iron  rollers  a  a,  which 
by  means  of  the  screw  b  &,  operating  upon  the  shaft- 
journals,  can  be  more  or  less  drawn  together.  Both 
rollers  are  supplied  on  the  one  end  of  the  shaft  with 
spur-wlieels,  by  means  of  which  the  motion,  which  the 
one  roller  receives  by  the  motive  power  of  the  establish- 
ment, is  transmitted  to  the  other  roller  also.  Above 


90 


MANUFACTURE   OF    STARCH,    ETC. 


the  rollers  the  hopper  d  is  situated,  for  receiving  the 
steeped  wheat.  In  order  to  place  the  grain  very  evenly 
between  the  braising  rollers,  there  is  in  the  hopper  a 
third  roller  of  a  small  diameter,  e,  which  on  one  of  its 

Fig.  20. 


Apparatus  for  crushing  the  steeped  wheat. 

ends  is  also  provided  with  a  spur-wheel.  Into  this 
wheel  fit  the  teeth  of  the  wheel  c,  which  is  situated  on 
one  of  the  bruising  rollers,  thereby  causing  the  turning 
of  the  thinner  roller  simultaneously  with  that  of  the 
bruising  roller.  By  the  revolving  of  the  thinner  roller 
the  wheat  in  the  hopper  is  carried  away  evenly  from 
the  slit  formed  by  two  inclined  surfaces,  which  are 
placed  above  the  third  roller,  and  is  thus  brought  be- 
tween the  bruising  rollers.  The  quantity  of  the  grain 


THE  TECHNOLOGY  OF  STARCH.          91 

desired  to  be  placed  between  the  rollers  is  regulated 
by  the  ledge,  which  is  provided  with  a  screw.  The 
crushed  substance  falls  into  the  case  #,  which  is  open 
on  one  of  its  sides.  It  becomes  obvious  that,  for  the 
process  of  crushing,  the  setting  of  the  rollers  is  the 
most  important  part ;  the  rollers  must  not  allow  one 
single  grain  to  pass  without  being  bruised,  but  at  the 
same  time  must  not  crush  the  starch  granules.  In 
some  manufactories  an  arrangement  exists  by  which 
from  the  steeping  cistern  a  conveyor  (creeper)  is  con- 
ducted to  the  hopper  of  the  crusher-mill  for  the  pur- 
pose of  again  washing  out  the  wheat,  by  letting  more 
water  run  over  it,  while  on  the  way. 

b.  The  Fermenting  of  the  bruised,  ground-it,})  Wheat. — 
The  crushed  wheat,  in  order  to  allow  it  to  ferment,  is 
transferred  from  the  crushing  mill  to  the  fermenting 
or  working  tank  (gyle-tun),  which  like  all  other  vessels 
made  of  oak  wood  has,  prior  to  its  use,  to  be  scoured 
out  with  hot  water. 

The  large  vats  are  filled  with  boiling  hot  water,  and 
the  smaller  utensils  made  of  oak  wood  are  placed 
therein.  The  vats  are  closed  by  placing  their  wooden 
lids  thereon,  and  thus  filled  they  are  left  for  three  days 
to  macerate.  During  this  time  the  greater  part  of 
the  tannic  and  gallic  acid  is  sufficiently  extracted  by 
the  water.  After  the  lapse  of  this  time,  the  water  is 
drained  out,  and  the  vats,  etc.,  again  rinsed  out  with 
cold  water.  If  this  is  omitted,  the  first  starch  obtained 
will  be  of  a  yellow  color  instead  of  being  white.  In 
the  fermenting  tub,  the  wheat  substance  is  above  all 
covered  with  the  requisite  quantity  of  water  and  stirred 
up  into  a  thick  liquidy  mass.  During  the  summer  sea- 
son, pure  river  water  is  used  for  diluting  ;  during  the 
winter,  sour  waters  are  added,  i.  e.,  the  sour  liquid 


92  MANUFACTURE    OF    STARCH,    ETC. 

which  has  been  previously  drained  off  from  the  starch. 
This  admixture  acceherates  the  process  of  fermentation. 
Some  recommend  also  the  use  of  leaven  or  yeast. 

After  the  lapse  of  some  time  a  scum  is  formed  upon 
the  contents  of  the  fermenting  tub,  and  a  thick  paste 
similar  to  the  dough  in  the  baking  trough  begins  to 
rise;  and  it  must  now  be  observed,  that,  after  the 
dough  has  fully  risen,  it  is  well  worked  up  by  ap- 
plying wooden  rakes,  to  cause  that  substance  which 
has  settled  on  the  bottom  also  to  rise.  After  the  fer- 
mentation is  perfected,  the  mass  will  again  settle, 
that  is,  sink  back  to  its  original  volume.  Of  course, 
the  raking  or  mashing  of  the  mass  is  to  be  repeated 
as  often  as  the  substance  ferments  and  rises  ;  and  when 
the  fermentation  has  ceased,  it  is  called  "ripe." 

The  duration  of  the  fermenting  process  varies  greatly 
and  depends  essentially  on  the  temperature  which  pre- 
vails in  the  fermenting  room.  It  should  not  exceed 
20°  C.  (68°  F.),  in  which  case  the  period  of  fourteen 
days  would  suffice.  Di  ring  the  summer  season  this 
temperature  can  be  attained  more  easily  by  a  proper 
ventilation  of  the  fermenting  place,  but  during  the 
winter  season  a  heating  apparatus  is  required  in  order 
to  keep  up  the  proper  temperature,  and  to  avoid  having 
the  fermentation  ensue  too  slowly  or  even  cease  entirely. 
The  fermentation  can  be  accelerated  in  cold  seasons  by 
the  application  of  some  sour  ivater,  and  it  is  usually  fin- 
ished, whenever  the  liquid  appears  of  a  yellowish  tint, 
and  is  covered  with  an  unbroken  surface  of  fungi 
(usually  of  the  species  of  Pencillium  ylaucum).  When 
kneaded  in  the  hand,  it  easily  parts  with  the  starch 
while  the  hulls  freed  of  the  starch  remain. 

The  following  explains  the  chemical  process  which 
takes  place  during  the  fermentation.  When  the 


THE  TECHNOLOGY  OP  STARCH.         93 

steeped  and  crushed  wheat  has  been  placed  in  the 
water,  the  latter  dissolves  the  gum,  the  sugar,  the 
albumen  and  diverse  salts,  while  the  hull,  the  germs, 
the  starch,  the  gluten,  and  sundry  other  salts  are  not 
dissolved.  But  such  a  solution  will  gradually  ferment 
by  the  admission  of  the  air  in  which  fungous  matter 
is  always  contained,  and  this  can  be  accomplished 
still  more  rapidly  when  sour  water  is  added,  wherein 
fungi  already  present  are  developed.  At  first  the 
fermentation  ensuing  is  alcoholic  and  hence  accom- 
panied by  developing  gas ;  this  causes  the  rising 
of  the  substance  and  the  forming  of  scum  matter. 
Soon  thereafter  from  the  alcohol  acetic  acid  forms,  as 
the  sour  smell  will  indicate;  then  other  fermentations 
will  take  place,  such  as  lactic  acid  and  butyric  acid 
fermentations  ;  and  the  mass  becomes  gradually  more 
sour.  By  -the  acids  formed,  the  gluten  is  partly  dis- 
solved, partly  softened,  and  its  composition  so  loosened 
as  to  be  deprived  of  its  refractory  and  pasty  proper- 
ties. In  the  further  course  of  the  process  the  putrid 
decomposition  of  the  gluten  begins  as  also  that  of  the 
albumen,  whereby  the  disaggregation  of  the  indissolu- 
ble portion  of  the  former  is  enhanced. 

The  effect  of  the  acids  and  of  the  ensuing  putrefac- 
tion upon  the  gluten  is,  in  fact,  what  is  intended  by 
the  process  of  fermentation.  The  starch  granules  are 
partly  freed  from  the  gluten  which  envelops  them,  and, 
on  the  other  hand,  the  gluten  is  placed  in  a  condition 
easily  to  emit  the  starch  granules  during  the  act  of 
washing.  But  the  putrid  fermentation  must  not  pro- 
gress too  far,  because  the  starch  granules  may  be 
affected  thereby,  or  at  least  suffer  in  their  color;  the 
liquid  too  may  become  too  slimy,  if  too  much  gluten 


94 


MANUFACTURE    OF    STARCH,    ETC. 


enters  into  the  solution,  and  this  will  hinder  the  sepa- 
ration of  the  starch. 

The  grinding,  bruising,  or  crushing  is  also  performed 
either  between  the  burr-stones  of  a  flour  mill,  or  by 
crushing-rollers,  such  as  are  commonly  used  for  grind- 
ing steeped  wheat,  etc.  Of  these  machines,  there 


Fig.  21. 


Malting  mill  of  Allsopp's  construction. 

are  many  in  vogue,  and  of  different  construction;  that 
of  Allsopp  has  the  merit  of  performing  most  excellent 
work.  The  general  construction  and  arrangement  of 
the  apparatus  is  like  that  of  all  other  malting  mills. 
The  spiral  screw  (screw  of  Archimedes)  A,  serves  for 
the  transmission  of  the  crushed  wheat  to  the  steeping 
and  fermentation  vats.  The  coarsely  ground  wheat  is 
mixed  with  the  water  and  sour-water  in  the  tubs,  serv- 
ing both  for  fermenting  and  steeping  vats.  Under  any 


THE   TECHNOLOGY   OF    STARCH.  95 

circumstances,  it  is  best,  previously,  to  pour  into  these 
vats  a  few  pails  of  water  to  avoid  the  adherence  of  the 
ground  wheat  upon  the  bottom  of  the  vats,  causing 
unnecessary  trouble  and  work  afterwards.  After  the 
tubs  have  been  one-third  filled  with  ground  wheat, 
and  the  formed  lumps  have  been  stirred  by  the  use  of 
rakes,  so  much  pure  water  must  be  added  that  it 
covers  the  grain.  The  mass  is  then  carefully  stirred 
up  until  it  acquires  the  consistency  of  a  thin  paste. 
Thereupon,  the  tubs  are  filled  up  two-thirds  with 
ground  wheat,  the  same  again  stirred  up,  the  corre- 
sponding quantity  of  water  again  poured  in,  and  the 
entire  mass  stirred  as  before.  Finally  the  last  third 
of  the  vats  is  filled  up  with  the  grain,  and  again  so 
much  water  added  as  will  cover  the  kept-down  sub- 
stance. The  entire  mass  is  again  stirred  diligently, 
until  it  becomes  so  thin  that  the  paddle  may  be 
thrust  through  to  the  bottom  of  the  same  in  every 
direction.  By  this  treatment  an  evenness  of  the  mass 
is  obtained,  which  not  only  furthers  the  ensuing  of  the 
fermentation,  but — as  experience  proves. — also  favors 
the  result  generally. 

After  the  lapse  of  twenty-four  hours  examination 
is  made,  whether  the  substance  is  much  swelled.  If 
it  is  noticed  that  the  grain  has  risen  very  high  but  is 
yet  too  dense,  more  water  is  added,  and  all  is  again 
stirred.  The  surest  test  of  the  mass  being  rightly 
steeped  consists  in  this,  that  after  twenty-four  hours' 
soaking  it  runs  freely  off  the  stirring  paddle.  The 
mash  rising  up  in  the  centre  "is  called  "regulus." 

The  mass  is  now  left  to  ferment  by  leaving  it  un- 
disturbed from  the  day  of  mashing — in  summer  from 
five  to  seven  days,  in  the  winter  from  ten  to  fourteen 
days — according  to  the  higher  or  lower  temperature. 


96  MANUFACTURE    OF    STARCH,    ETC. 

But  if  the  mass  should  rise  too  high,  the  "regulus" 
rising  in  the  centre  is  gently  pressed  down,  to  prevent 
the  air  from  drying  it  out,  but  without  disturbing  the 
mass  itself.* 

c.  Separating  the  Starch  from  the  Fermented  Mass. 
— After  the  mass  has  attained  the  proper  degree  of 
ripeness  in  the  fermen ting-vats,  the  impure  yellow 
liquid  is  drained  off  as  much  as  possible,  and  there- 
upon the  separating  of  the  starch  from  the  mass  begins. 

The  drained-off  acidulous  liquid  contains  besides  the 
gluten,  acetic  acid,  lactic  acid,  butyric  acid,  small 
portions  of  succinic  acid,  salts  of  ammonia,  some  sul- 
phate of  hydrogen,  and  also  the  greater  part  of  the 
mineral  ingredients  of  the  wheat,  especially  phos- 
phates of  clay.  This  substance,  mixed  with  remnants 
formed  in  making  starch,  serves  as  swill  for  the  food 
of  animals  or  as  a  fertilizer,  especially  when  the  liquor 
has  previously  been  neutralized  by  chalk. 

In  all  the  larger  establishments  for  manufacturing 
starch,  the  separating  of  the  same  from  the  fermented 
mass  is  at  present  performed  by  a  sieve-like  perforated 
wooden  or  copper  drum  (washing-drum)  which  revolves 
around  its  axis. 

Figs.  22  and  23  represent  a  washing-drum  of  recent 
construction. 

Two  spur-wheels,  a,  lined  with  wood  between  the 
spokes,  form  the  side  walls  of  the  drum.  The  drum 
itself,  which  is  from  1.1  to  1.25  metres  (3.6  to  4.1  feet) 
long,  has  a  diameter  of  1.25  metres,  consisting  of  a 
perforated  copper-plate,  which  connects  with  the  sides 

*  The  advnntage  of  grinding  the  wheat  before  steeping  it  con- 
sists chiefl}'  in  avoiding  the  time  absorbing  soaking  of  the  whole 
grain.— HUTTEB. 


;    T.eA,rLJN  OLOGY    OF   STARCH. 
Fig.  22. 


97 


Diagram  of  Washing  Drum  of  recent  construction  for  separating  starch 
from  the  mash. 

Fig.  23. 


Longitudinal  view  of  same. 


98  MANUFACTURE    OF    STARCH,    ETC. 

by  being  riveted  to  the  cast  rims  of  the  same. 
Through  the  shaft  of  the  drum,  i.  e.,  the  stuffing  boxes 
in  the  shaft  beds  of  the  sides,  passes  the  water  pipe  &, 
which  is  also  perforated,  inside  of  the  drum.  This  pipe 
is  likewise  covered  in  the  drum  by  a  perforated  pipe  c, 
of  24  to  32  centimetres  (9.45  to  12.6  inches)  in  diame- 
ter,11 whereby  the  stopping  (clogging  up)  of  the  open- 
ings of  the  water-pipe  is  prevented.  For  filling  and 
emptying  the  drum  the  gate  marked  d  is  used. 

After  the  drum  has  been  filled  with  the  fermented 
mass  of  from  6  to  12  hectolitres  (16.8  to  33.6  bushels) 
of  wheat,  water  is  conducted  into  the  water-pipe,  and 
the  drum,  by  means  of  the  pulley  e,  makes  a  slow  re- 
volution in  the  direction  of  the  dart.  The  raw-starch 
milk  flows  from  the  drum  into  the  box/J  which  is  put 
underneath  the  drum,  this  box  running  upon  rollers. 
From  thence  the  starch-milk  flows  through  a  spout 
in  the  depositing  vat.  After  the  lapse  of  from  three- 
quarters  of  an  hour  to  an  hour  and  a  quarter  the  mass 
is  completely  washed  out.  The  box  is  withdrawn  from 
under  the  drum,  the  door  of  the  drum  opened,  and 
turned  so  that  the  opening  is  below,  and  the  residue 
is  allowed  to  fall  into  the  funnel  </,  which  carries  it  to 
the  place  of  storage. 

This  residue  is  a  mixture  of  hulls,  a  part  of  the  mostly 
uninjured  oily  germs,  and  the  adhering  softened  and 
sour  gluten.  It  serves  as  food  for  hogs,  and  may  also 
be  applied  for  the  mixing  of  the  sour-water. 

The  raw-starch  milk  contains  the  starch,  glutinous 
starch,  finely  divided  sour  gluten,  and  finely  divided 
hulls,  augmented  by  such  substances  of  the  wheat,  as 
have  been  dissolved  by  the  acids,  created  during  the 
fermentation. 

A  more  complicated  apparatus  for  separating  the 


THE  TECHNOLOGY  OF  STARCH.          99 

starch  from  the  fermented  substance,  is  the  so-cafled 
tread'mg-mill,  which  is  still  used  in  some  establish- 
ments. 

d.  The  Refining  of  Hie  Raw  Starch. — The  starch-milk 
flowing  from  the  wash-drum  contains,  as  has  been 
stated,  besides  the  starch  also  glutinous  starch,  finely 
separated  sour-gluten,  and  the  finely  divided  hulls  of 
the  wheat,  impregnated  wTith  substances  which  were 
brought  into  solution  by  formed  acetic,  lactic,  and 
other  sour  agents  during,  fermentation.  This  starch- 
milk  is  now  directly  conducted  to  the  deposit  vat. 
Generally  there  are  two  such  vats  in  every  establish- 
ment, each  of  them  having  a  capacity  of  about  20 
hectolitres  (56  bushels)  of  wheat.  In  the  vats  a  stir- 
ring appliance  is  affixed  which  can  be  brought  into 
connection  with  the  motive  power  of  the  manufac- 
tory. This  stirring  apparatus  can  be  raised  and  lowered 
at  will.  The  stirrer  used  for  the  manufacture  of  potato 
starch  is  for  this  purpose  likewise  suitable. 

When  a  deposit  vat  has  been  filled — in  case  the 
starch-milk  is  not  thin  enough  more  water  is  added — 
the  stirring  apparatus  is  set  in  motion  in  order  to  com- 
pletely stir  up  and  mix  the  contents  of  the  vat.  After 
the  raising  of  the  stirrer,  the  starch-milk  is  left  to  settle 
for  a  period  of  about  four  days.  After  this  period  the 
suspended  substances,  that  is,  the  starch,  the  glutinous 
starch,  the  sour  disaggregated  gluten,  and  the  hull 
fragments  have  settled  to  the  bottom.  Since,  however, 
the  specifically  heavier  starch  granules  are  deposited 
much  faster  than  the  glutinous  starch,  the  gluten  and 
the  hulls,  therefore  the  heavier  starch  occupies  the 
lower  part  of  the  layer  which  rests  on  the  bottom 
of  the  tank;  above  it  rests  the  glutinous  starch;  on 
the  top  is  found  a  slimy  liquid  layer,  composed  of  yel- 


100  MANUFACTURE    OF    STARCH,    ETC. 

lowlsh,  sour  gluten  and  fine  portions  of  hulls.  A  sharp 
division  of  these  layers  does  not  take  place,  but  a  gra- 
\  dual  transition  from  one  layer  to  the  other  occurs. 
The  liquid  standing  above  the  deposit  in  the  vat  is 
gradually  drained  off  through  the  bungholes  until  the 
slimy  portion  of  the  deposit  is  reached.  This  slimy 
layer  is  then  also  withdrawn — but  in  a  separate  ves- 
sel— in  order  to  gain  the  starch  contained  therein. 
After  the  closing  of  all  the  bungholes,  pure,  clear- 
water — best  well  water — is  poured  into  the  deposit 
vat,  the  sediment  again  thoroughly  stirred  up,  and  the 
starch-milk,  run  through  a  fine  hair-sieve,  is  divided 
into  other  depositing  tubs.  This  sifting  is  done  for 
the  purpose  of  completely  removing  remaining  impu- 
rities— particularly  the  finely  divided  hulls — and  is 
carried  out  in  the  following  manner:  the  white  starch 
deposited  in  the  vats  is  gradually  loosened  to  the  bot- 
tom, by  means  of  the  so-called  "bleak"  or  '-May" — a 
two-edged  10  to  11  centimetre  (3.94  to  4.33  inches) 
broad  knife  of  the  shape  of  a  spade — so  that  the 
entire  sediment  is  cut  into  small  pieces,  arid  nothing 
thereof  sticks  to  the  vat.  The  starch- mass  is  thereby 
enabled  completely  to  receive  the  water  poured  thereon, 
and  to  mix  therewith  easily.  The  fresh  water  is  poured 
about  48  centimetres  (1.57  feet)  high  above  the  starch- 
mass,  and  stirred  well,  either  with  the  rake  or  the  stirring 
apparatus,  until  the  whole  is  a  uniform  liquid,  and  no 
more  solid  pieces  adhere  to  the  bottom,  whereupon  the 
vessels  are  filled  up  entirely  with  pure  water,  and  all 
is  again  well  stirred.  The  white  starch-milk  is  then 
strained  through  the  hair  sieve  into  one  or  several  well- 
rinsed  depositing  vats  or  washing-tubs.  The  sieve  is 
placed  for  this  purpose  on  two  round  (smooth  and 


THE    TECHNOLOGY   O^    STAKCK.  101 

clean)  poles  which  are  placed  at  a  proper  distance 
parallel  and  above  the  depositing-tub,  and  as  often  as 
the  same  has  been  filled  with  starch  milk,  to  be  shaken 
on  these  poles  to  and  fro.  If  the  sieve  gets  clogged 
up  in  consequence  of  the  hulls  or  bran  depositing  on 
the  bottom  of  the  same,  some  pure  water  is  poured 
thereon,  and  it  is  permitted  to  run  into  the  depositing 
vats.  Thereupon  the  sieve  is  put  upside  down,  and 
some  more  fresh  water  is  poured  on  the  lower  side  of 
the  same.  By  this  simple  operation  all  foreign  ingre- 
dients can  be  removed  with  ease,  and  the  starch-milk 
can  again  pass  through  the  sieve  without  hindrance. 
Should  the  starch  substance  in  the  depositing  vats 
have  become  somewhat  too  thick  in  the  lower  part  of 
the  tank  in  consequence  of  the  starch  having  again 
somewhat  settled  during  the  previous  work,  more  water 
should  be  added,  and  well  stirred  up.  The  strained 
starch-milk  must  also  be  occasionally  stirred  in  order 
to  separate  the  small  hull  particles  which  have  pressed 
through  the  sieve,  and  other  bodies,  not  belonging  to 
the  starch-mass,  which  float  on  the  surface,  as  well  as 
any  acidulous  matter  which  may  yet  adhere  to  the 
starch.  If  this  operation  is  not  conducted  with  great 
care  it  may  easily  occur  that  the  starch  produced  will 
be  full  of  holes,  poor  looking,  and  as  a  consequence 
not  be  desirable  in  commerce.  The  same  might  also 
happen  in  case  the  starch  is  left  too  long  in  the  de- 
positing vats. 

It  is  also  recommended  to  effect  the  straining  of  the 
starch  under  water,  whereby  the  yield  of  starch  can  be 
greatly  increased.  If  a  sieve  is  used  with  such  narrow 
meshes  that  it  is  impossible  for  the  starch  granules  to 
pass  through,  they  will  deposit  themselves  on  the  sieve 


102  SlA^UFAOTtfR"E   OF    STARCH,    ETC. 

bottom,  and  the  process  of  straining  will  take  place 
only  in  drops;  hence  this  process  of  straining  on  a 
larger  scale  is  inadmissible.  But  if.  on  the  other  hand, 
the  sieve  containing  the  starch,  which  is  to  be  refined, 
is  placed  under  water,  instead  of  pouring  the  starch 
containing  water  upon  the  cloth,  the  water  impreg- 
nated with  the  starch-granules  will  be  raised  and  flow 
to  the  surface,  and  force  the  starch  along,  leaving  the 
foreign  substances  to  settle  on  the  bottom  of  the 
sieve.  This  will  be  easily  accomplished  by  turning 
and  shaking  the  sieve  during  the  operation. 

The  apparatus  serving  for  this  purpose  consists  of, 
1,  a  wooden  tank ;  2,  of  a  second  wooden  vessel  or  box 
of  somewhat  smaller  dimensions,  fitting  accurately  in- 
side of  the  first  tank,  its  bottom  composed  of  silk 
gauze ;  3,  of  an  undershot  paddle-wheel,  whose  shaft 
rests  upon  two  bearers,  being  fastened  on  the  rim  of 
the  larger  tank.  By  the  mechanism  of  this  wheel  the 
sieve  can  be  given  a  shaking  motion,  or  an  alternate 
motion  up  and  down.  The  impure  starch  is  admitted 
through  a  gum  hose  into  the  sieve,  while  the  water 
impregnated  with  the  starch,  that  has  passed  through 
the  sieve,  flows  off  through  another  siphon-shaped 
pipe. 

The  depositing-troughs,  made  of  pine  wood,  are  about 
1  metre  high,  and  0.8  to  1  metre  (2.62  to  3.28  feet) 
wide,  tapering  off  somewhat  conical ly  towards  the 
bottom.  They  are  also  supplied  with  bung-holes,  at 
different  heights,  for  the  draining  off  of  the  water.  The 
shape  of  these  depositing-troughs  is  delineated  in  Fig. 
24.  They  are  about  64  centimetres  (2.1  feet)  in  width, 
and  are  at  present  more  commonly  used  than  the  tubs. 

The  aim  should  be  to  divide  the  starch  milk  very 


THE    TECHNOLOGY    OP    STARCH.  103 

evenly  in  the  smaller  vessels,  and  if  necessary  it  should 

be  diluted  with  fresh,  cold  well  water,  and  well  stirred 
i 

Fig.  24. 


Depositing-trough  for  refining  wheat  starch. 

so  as  to  obtain  an  equal  mixture.  In  these  small  de- 
positing vats,  the  starch  milk  remains  until  a  complete 
deposit  of  the  suspended  substance  is  effected.  This 
occurs  within  three  days.  Then  the  liquid  standing 
over  the  residuum  is  carefully  drained  offj  and  if  neces- 
sary the  upper  portion  is  also  removed  by  a  careful 
edulcoration  (washing),  until  the  pure  starch  appears. 
This  operation  may  be  facilitated  by  the  aid  of  a  moist- 
ened feather- wing.  The  edulcorated  mass  is  placed 
in  separate  basins  (receivers),  for  further  operations. 

A  repeated  edulcoration  of  the  starch  is  usually  not 
resorted  to,  although  it  is  self-evident,  that  by  so  doing, 
a  greater  purity  of  the  product  is  attained.  Too  fre- 
quent edulcoration,  however,  is  avoided  for  the  simple 
reason  that  starch  so  treated  thereby  loses  the  property 
of  forming  a  cohesive  substance  when  dried,  a  qualifi- 
cation imperatively  demanded  in  commerce.  As  soon 
as  the  deposited  starch  no  longer  colors  blue  litmus  paper 
red  when  pressed  thereon,  it  proves  itself  free  from 
acid  and  also  free  from  soluble  substances  generally. 


104  MANUFACTURE    OF    STARCH,    ETC. 

Far  more  expeditiously  and  completely  than  by  stir- 
ring, depositing,  settling  off,  etc.,  or  by  channelling, 
can  the  process  of  refining  be  attained  by  the  use  of  a 
centrifugal  machine,  which,  in  order  to  distinguish  it 
from  the  other  starch-refining  apparatus,  is  by  its 
inventor  termed — 

The  ft  aw- Starch  Centrifugal  Machine. — This  appa- 
ratus differs  from  the  usual  machines  of  this  kind  by 
its  drum  not  being  a  sieve-drum,  and  hence  no  liquid 
will  be  hurled  out  of  it.  If  gluten-starch,  etc.,  or 
rather  impure  starch-milk  is  admitted  into  the  revolv- 
ing centrifugue,  the  same  process  occurs  as  has  been 
explained  in  the  operation  of  a  similar  apparatus  for 
rectifying  potato-starch.  The  suspended  substances 
of  the  starch  milk  deposit  themselves  on  the  sides  of 
the  drum,  rotating  according  to  their  density  and  re- 
spective specific  gravity.  In  the  outer  line  the  starch 
is  deposited,  then  the  dressing  and  the  gluten,  and  as 
the  liquid  (the  water),  as  has  already  been  stated,  is  not 
hurled  out,  but  being  of  the  least  densit}^  and  also  of 
the  least  specific  gravity,  it  forms  the  innermost  stratum 
in  the  apparatus.  After  the  drum  is  brought  to  a  stand 
still,  the  liquid  of  course  runs  to  the  bottom  of  the 
drum,  and  can  by  means  of  an  opening,  which  can  be 
closed  during  the  working  of  the  machine,  flow  off. 
This  having  been  attended  to,  the  impure  layer  pf  the 
gluten  and  dressing  can  be  removed  from  the  drum. 
The  gluten-starch,  thus  separated,  forms  a  yellowish- 
gray  past?  which,  when  ground,  furnishes  a  flour  con- 
taining from  5  to  6  per  cent,  gluten. 

For  practical  purposes  it  would  be  best  not  to  apply 
at  once  the  centrifugal  apparatus  in  operating  the 
raw-starch  milk  as  soon  as  it  is  taken  from  the  wash- 


THE  TECHNOLOGY  OF  STARCH.         105 

ing  drum,  but  to  allow  it,  after  stirring,  first  to  settle 
for  several  days,  then  to  draw  off  the  liquid  in  order 
carefully  to  remove  the  upper  (slimy)  layer,  then  to 
stir  up  the  raw-starch  in  water  and  finally  apply  the 
raw-starch  centrifugal  machine.  By  means  of  this 
apparatus,  the  operation  is  performed  in  a  few  hours, 
which  by  the  older  method  of  stirring,  precipitating, 
and  by  inclining  gutters,  can  only  be  effected  in  as 
many  days  and  moreover  not  so  efficaciously.  By 
application  of  the  centrifugal  apparatus  for  refining 
starch,  the  last  process  of  purifying  the  same  is 
effected. 

e.  The  Process  of  Drying. — While  potato-starch 
cannot  well  be  manufactured  during  the  summer 
season  with  profit,  on  account  of  the  scarcity  of  the 
raw  material,  the  manufacture  of  wheat-starch  is  with 
some  chiefly  the  work  of  that  warmer  season. 

What  has  been  said  with  regard  to  the  drying  of 
potato-starch,  is  also  generally  applicable  in  the  drying 
of  wheat  starch.  Let  us  suppose  the  starch  has  been 
cleaned  in  the  depositing  tubs  or  vats,  and  left  therein 
to  be  "dug  out."  To  prepare  it  for  this,  some  of  the 
water  which  it  yet  holds  absorbed,  and  still  contains, 
must  first  be  extracted.  This  was  formerly  effected 
(mid  in  smaller  establishments  is  even  to  this  day) 
by  covering  it  with  some  clean  cloths  which  are  often 
changed  and  wrung  out.  This  operation  is  finished 
whenever  the  starch-cake  no  longer  appears  spongy 
in  the  centre,  but  solid.  If  some  dry  starch  is  thrown 
on  these  cloths  (so  as  to  cover  them  several  inches), 
it  will  absorb  the  moisture  eagerly,  and  the  starch  may 
be  dug  out  after  the  lapse  of  but  a  few  hours.  This 
digging  is  performed  with  an  instrument  like  a  spatu- 


106  MANUFACTURE   OF    STARCH,    ETC. 

la,  or  with  a  long  knife  with  a  narrow  back.  The  starch 
mass  in  the  tub  is  cut  twice  (crosswise)  down  to  the 
bottom.  This  manipulation  furnishes  four  pieces  in 
every  tub,  which  must  be  lifted  out  gently  and  care- 
fully. The  withdrawing  of  the  first  piece  is  made 
easier  by  inserting  into  one  of  the  cuts  a  hard,  thin 
piece  of  board  of  about  32  centimetres  (12.6  inches) 
in  length;  and  after  loosening  the  other  pieces  care- 
fully all  around  with  the  knife,  firmly  taking  hold  of 
the  piece,  at  the  same  time  grasping  as  deeply  as  possi- 
ble into  the  cut,  lifting  the  starch  on  the  board  designed 
for  carrying  it  away,  and  in  such  a  manner  that  the 
starch  is  neither  broken  nor  pulled.  The  other  pieces 
can  then  be  removed  with  greater  facility.  But  by 
inserting  the  board  into  the  cut  the  same  must  be 
moved  gently  to  and  fro,  in  order  to  loosen  the  starch 
on  all  its  sides  without  tearing  it  asunder.  But  far 
more  simple  and  easy  is  the  digging  out  of  the  starch 
from  the  depositing  chests.  Pieces  about  32  centi- 
metres (12.6  inches)  square  are  formed  therein,  that 
is,  of  one-half  the  size  of  the  width  of  the  chest.  This 
circumstance  explains  sufficiently  the  reason  why 
these  depositing  chests  are  preferable  to  the  tubs, 
independent  even  of  the  more  convenient  shape  which 
the  starch-cakes  thus  obtain.  The  pieces  dug  out  are 
placed  in  the  drying-room  and  weighed  down  with 
bricks.  In  the  course  of  about  twenty -four  hours, 
these  bricks  absorb  a  great  quantity  of  moisture  from 
the  starch-cake.  Instead  of  bricks,  slabs  of  gypsum 
may  be  used,  and  also  upon  such  slabs  the  starch 
pieces  may  be  laid. 

In  larger  establishments,  and  especially  in  those  of 
a  more  recent  construction,  the  preparatory  drying  of 


THE   TECHNOLOGY    OF    STATCCII.  107 

the  starch  mass  is  generally  no  longer  performed  by 
applying  cloths,  bricks,  and  gypsum  slabs,  but  by 
means  of  air-pumps.  The  starch  is  then  Brought  into 
the  drying-room,  where  at  a  temperature  gradually 
approaching  60°  C.  (140°  F.)  the  last  remains  of  mois- 
ture are  taken  off.  In  order  to  be-  convinced  of  the 
perfect  dry  ness  of  the  starch,  a  piece  is  broken  in 
two,  and  the  break  is  scraped  with  the  nail  of  the 
thumb.  If  a  gnashing  or  crackling  sound  is  observed, 
and,  moreover,  if  upon  the  angular  side  of  the  fracture 
longitudinal  stripes  are  seen  running  together,  such 
are  to  be  considered  as  a  sign  of  an  excellent  starch, 
and  the  starch  is  then  finished  to  perfection. 

23.  Methods  without  Fermentation. — The  reason  for 
endeavoring  to  substitute  for  the  manufacture  of 
wheat-starch  by  fermentation  another  method  by 
which  the  process  of  fermenting  is  avoided,  has  already 
been  stated.  By  fermentation,  the  greater  .part  of  the 
nutritious  substance  of  the  wheat  is  destroyed  and 
run  off,  so  especially  the  gluten,  an  ingredient  con- 
tained therein  in  abundance.  Such  a  loss  of  useful 
substances,  considered  from  an  economical  point  of 
view,  is  truly  deplorable.  But  we  feel  that  the  general 
introduction  of  the  manufacture  of  starch  from  wheat 
without  fermentation  is  impeded  or  rendered  difficult, 
as  otherwise  the  process  of  fermentation  would  have 
been  abandoned  long  ago.  What  can  this  obstruction 
be?  Although  by  the  method  of  fermenting,  the 
starch  is  being  furnished  in  the  easiest  and  most  per- 
fect manner,  yet  by  the  methods  without  fermentation 
the  gluten  is  obtained  in  such  a  condition  as  not  to  be 
at  once  fit  for  food.  Although  gluten  possesses  a 
great  value  as  a  nourishing  protein  substance,  when  it 
is  intermixed  with  starch,  as  in  flour,  but  just  so  little 


108  MANUFACTURE   OF    STAHCH,    ETC. 

is  it  suitable  as  an  article  of  food  in  its  crude  state, 
as  is  proyen  in  the  manufacture  of  starch  without 
fermentation.  It  must  previously  be  deprived  of  its 
sticky,  glutinous  condition,  or  by  mixing  it  with  suit- 
able substances  must  be  divided.  In  all  methods  of 
manufacturing  wheat-starch  without  fermentation  there 
must  at  the  same  time  be  considered  the  suitable  utiliza- 
tion of  the  gluten,  and  only  where  this  is  accomplished 
are  those  methods  profitable.  Every  judicious  proposi- 
tion for  using  the  gluten  to  advantage,  is  a  further  step 
in  the  development  of  manufacturing  starch  without 
the  process  of  fermentation,  and  every  improvement  in 
this  process  for  increasing  the  yield  of  starch  furthers 
the  propagation  of  that  method.  There  are  two  differ- 
ent methods  of  making  wheat-starch  without  the  pro- 
cess of  fermentation,  and  moreover  to  also  obtain  the 
gluten,  i.  e.,  the  method  of  working  the  whole  grain, 
and  the  method  of  operating  the  ground  wheat  (flour). 

THE  MANUFACTURE  OF  WHEAT  INTO  STARCH, 
WITHOUT  GRINDING-  THE  "WHEAT. 

This  method  is  essentially  the  same  as  has  been 
mentioned  for  the  testing  of  the  wheat,  with  regard 
to  its  yield  of  starch  generally.  It  begins  with  the 
same  operations,  by  which  the  fermentation  process 
commences,  namely  with  the  steeping  and  crushing 
of  the  wheat.  The  well-cleaned  wheat  is  saturated 
with  water  and  left  to  macerate  until  the  grains  can 
be  easily  pressed  between  the  finger  ends,  and  thereby 
give  a  milky  juice.  During  the  warmer  season,  the 
steeping  water  must  be  frequently  renewed,  to  prevent 
it  from  becoming  sour  and  of  bad  smell.  It  is  very 
proper  to  apply  tepid  water,  for  hastening  the  steeping 


THE    TECHNOLOGY    OF    STARCH.  109 

process,  since  if  wheat  remains  too  long  in  the  water, 
the  gluten  softens,  becomes  smeary,  and  furthermore 
during  the  manipulation  of  washing  out,  part  of  it  is 
washed  away. 

The  wheat  amply  steeped  and  freed  from  the  adher- 
ing water  by  draining,  is  bruised  between  rollers  of 
stone  or  metal,  and  this  bruised  mass  is  best  again 
crushed  between  rollers,  after  having  previously  been 
pressed  out.  From  this  pasty  mass  the  starch  is  then 
separated  by  washing,  or  to  say  it  plainer,  the  starch 
is  separated  from  the  glitten  and  the  hulls.  That  this 
operation  does  not  take  take  place  as  fast  and  as  easy, 
as  is  the  case  when  the  sticky  gluten  that  envelops 
the  starch  is  previously  dissolved  or  disaggregated,  is 
obvious.  In  so-called  filter-bags  the  operation  suc- 
ceeds well  enough,  but  it  is  unhealthy  and  expensive. 
The  process  of  washing  out  in  the  drum,  being  also 
recommended,  can  hardly  result  more  favorably,  inas- 
much as  lumps  must  form  from  which  the  starch  can- 
not be  washed  out  by  the  water  which  is  flowing  upon 
them. 

Fesca  has  constructed  a  washing-apparatus  which 
fulfils  perfectly  all  the  objects  in  view.  The  raw- 
starch  milk  is  allowed  to  settle  for  from  20  to  24 
hours,  and  after  drawing  off  the  very  slightly  sour 
liquid,  the  raw-starch  paste  which  has  deposited  in 
the  vat  is  worked  in  the  raw-starch  centrifugal  appa- 
ratus. Here  it  is  separated  into  raw-starch  and 
gluten-starch,  which  latter  is  obtained  in  the  form 
of  a  yellowish-brown  paste,  and  furnishes,  when  dried 
and  ground,  a  flour  containing  from  5  to  6  per  cent, 
gluten.  The  raw-starch  is  subjected  to  a  fermenta- 
tion for  several  days.  This  is  accomplished  by  placing 
the  same  in  small  vats,  and  in  order  to  dissolve  the 


110  MANUFACTURE   OF    STARCH,   ETC. 

residuum  of  gluten,  it  is  finally  washed  and  finished 
in  the  "  refining  centrifugal  apparatus."  By  this 
method  a  greater  yield  of  starch  is  obtained  than  by 
the  common  process  of  fermenting,  and  one  equally  as 
large  as  when  the  latter  process  has  been  supported 
or  aided  by  the  use  of  the  raw-starch  centrifugal 
machine. 

THE  MANUFACTURE  OF  WHEAT  FLOUR  INTO  STARCH. 

The  obtaining  of  wheat-starch  and  gluten  from  the 
ground  wheat  or  flour,  is  a  method  introduced  by  _Z£ 
Martin,  which,  besides  rendering  a  larger  yield  ot 
starch  offers  also,  on  account  of  perfectly  utilizing  all 
the  residues  for  food,  yet  far  greater  advantages  than 
all  the  methods  thus  far  explained,  so  that  the  fact  that 
this  is  not  yet  generally  heeded  seems  remarkable. 
This  method  should  have  long  since  crowded  out  all 
other  modes  of  operation  for  producing  starch,  and 
should  be  exclusively  used.  Of  course  the  expense 
of  reducing  the  wheat  into  flour,  attending  this 
method,  is  also  to  be  considered,  while,  on  the  other 
hand,  the  value  of  the  bran  resulting  from  the  grinding, 
as  also  the  obtaining  of  sweet  gluten  in  separating 
the  starch,  must  be  deducted  from  such  expense. 

By  Martin's  method,  the  flour  is  kneaded — in  the  pro- 
portion of  100  to  40  of  water — into  a  stiff  dough,  either 
by  hand  or  by  a  kneading-machine.  After  the  dough 
has  laid  for  one  or  two  hours,  it  is  manipulated  in  parts 
in  a  fine  sieve,  under  a  continual  flow  of  a  jet  of  water, 
until  the  water  ceases  to  flow  off  milky,  when  the  glu- 
ten remains  as  a  gummous  tough  mass.  The  manual 
labor  in  this  case,  as  well  as  in  that  of  the  kneading,  is 
very  troublesome  and  slow,  and  therefore  very  expen- 


THE   TECHNOLOGY    OF    STAKCH. 


Ill 


sive,  and   has  consequently  been   supplanted   by  the 
application  of  machinery. 

Fig.  25. 


(Vertical  diagram.) 
Fig.  26 


(Upper  view.) 
Fig.  27. 


(Vertical  longitudinal  section.) 


1  Metre. 


Figs.  25,  26,  and  27.— Washing  apparatus  of  recent  construction,  for  extract- 
ing the  starch  from  the  wheat  flour  according  to  Martin's  method. 


112  MANUFACTURE    OF    STARCH,    ETC. 

i 

The  main  principle  of  the  different  kinds  of  ma- 
chinery which  serve  for  this  purpose  is  always  the 
same,  and  is  so  arranged  as  to  roll  thick  string-like 
noodles,  formed  from  the  dough,  under  a  gentle  pressure 
to  and  fro  upon  the  surface  of  a  sieve,  of  course  while 
water  is  kept  constantly  flowing  over  them.  These 
noodles  are  from  time  to  time  turned  over,  to  change 
their  surface.  Such  a  washing  apparatus  of  recent 
construction  is  delineated  in  Figs.  25,  26,  and  27.  F  F 
(Figs.  25,  26,  and  27),  wooden  troughs  of  2  metres 
(6.56  feet)  in  length  and  1.5  metres  (4.92  feet)  in  width. 
By  Fig.  25  it  becomes  plain  in  what  manner  one  part 
of  the  periphery  of  the  troughs  is  cut  out,  and  in  lieu 
thereof  is  covered  with  the  wire-cloth  C (7,  which  is 
drawn  over  wooden  frames.  Alongside  of  the  troughs 
are  wide  gutters  D  D,  which,  by  a  movable  apparatus 
for  the  flowing  off  of  the  water,  regulate  the  level  of 
the  liquid,  so  that  it  reaches  in  the  gutter  and  trough, 
up  to  half  of  the  height  of  the  wire-cloth,  while  all  the 
other  starch  containing  water  flows  off,  through  the 
higher  or  lower  placed  pipe  d  (Fig.  27),  into  the  col- 
lection vat  &. 

Above  the  common  partition  of  both  troughs  near  E 
(Figs.  25  and  26),  a  bent  piece  of  tin  is  fastened,  which 
serves  to  bring  back  the  waves  of  the  moved  liquid, 
so  as  to  prevent  an  overflowing  from  one  trough  into 
the  other.  A.  A.  are  two  iron  shafts  resting  upon  beds 
which  are  fastened  on  the  rims  of  the  troughs.  Each 
of  them  has  on  its  end  an  iron  (fork-shaped)  extension, 
and  on  these  are  fastened  the  ends  of  the  grooved 
wooden  rollers  B  B,  so  that  the  latter  can  revolve  freely 
in  them.  The  shafts  A  A  receive  through  the  cranks 
a  a  half  a  turn,  alternately  towards  the  one  or  the  other 
direction,  whereby  the  rollers  B  B  are  moved  to  and 


THE    TECHNOLOGY    OF    STARCH.  113 

fro  across  the  bottom  of  the  troughs.  At  the  begin- 
ning of  the  operation  the  turning  of  the  cranks  requires 
a  considerable  effort.  After  working  for  about  ten 
minutes,  however,  the  volume  of  the  dough  has  been 
greatly  diminished,  whereby  the  labor  becomes  essen- 
tially easier.  The  water  is  conducted  into  both  the 
troughs  by  means  of  copper  pipes  perforated  with  fine 
holes  (roses),  which  during  the  entire  operation  squirt 
thin  streams  of  water  upon  the  dough  which  is  kept 
moving  underneath.  For  the  kneading  of  the  flour,  a 
kneading  machine  moved  by  steam  power  is  used,  by 
which  within  from  10  to  12  minutes  from  400  to  500 
kilogrammes  (880  to  1100  Ibs.)  of  dough  can  be  pre- 
pared. 

The  dough  having  macerated  from  one  to  two  hours, 
and  the  gluten  having  absorbed  sufficient  moisture,  it 
is  then  worked  up  into  pieces  of  about  1  kilogramme 
(2.2  Ibs.)  in  size,  and  equal  portions  placed  in  the 
troughs.  The  next  operation  consists  in  the  moving 
to  and  fro  of  the  rollers.  The  man  attending  has  to 
observe  that  the  wire  sieves  do  not  become  stopped  up 
with  gluten,  and  if  this  should  be  the  case  to  clean  the 
same  by  means  of  brushes.  Besides,  in  case  the  dough 
balls  up  into  larger  lumps,  the  attendant  must  at  once 
divide  the  same. 

The  washing  out  of  the  dough — which  lies  partly 
under  water — takes  usually  one  hour,  and  will  be  under 
all  circumstances  entirely  finished  whenever  the  water 
flowing  off  no  longer  carries  along  any  particle  of  starch. 
The  waste-pipe  d  (Fig.  26)  is  then  entirely  withdrawn 
from  the  gutter  Z>,  whereby  the  liquid  contents  of  the 
gutter  and  trough  flow  off  into  the  reservoir  G. 

The  gluten  remaining  in  the  trough  is  freed  of  its 
surplus  water  by  five  minutes  constant  kneading,  then 


114  MANUFACTURE    OF    STARCH,    ETC. 

removed  from  the  trough  for  further  manipulation,  and 
the  apparatus  used  for  another  operation.  J.  B.  Polail- 
lon,  and  F.  Maillard,  of  L}rons,  recommend  for  pro- 
ducing starch  from  wheat  flour  the  following  method, 
without  kneading:  The  wheat  is  milled,  the  flour  freed 
of  the  bran,  mixed  with  an  ample  quantity  of  water,  and 
the  mixture  left  to  macerate  for  some  time — according 
to  the  quality  of  the  flour — but  the  decomposing  of  the 
gluten  must  be  avoided.  The  pasty  mass  is  worked 
through  a  fine  wire-sieve,  upon  which  simultaneously 
water  is  flowing  from  a  rose.  The  passing  of  the  mass 
through  the  sieve  is  accelerated  by  an  apparatus  which, 
while  rotating,  presses  on  the  same.  From  the  wire 
sieve  the  mass  flows  over  long  gutters  (inclined  planes), 
and  the  starch  deposited  therein  is  washed  in  the  man- 
ner already  described. 

Guided  by  the  previous  process,  Fesca  has  recently 
described  a  new  method  for  manufacturing  starch  by 
simply  applying  the  centrifugal  apparatus,  without  the 
kneading  of  the  dough.  According  to  this  treatment, 
the  wheat  flour  is  mixed  with  water  into  a  thin  paste, 
and  worked  in  the  raw  starch  centrifugal  machine,  where 
the  raw  starch  becomes  immediately  separated  from  the 
gluten  paste.  The  raw  starch  contains  almost  the 
entire  free  starch,  a  little  bran,  and  a  small  portion  of 
the  insoluble  gluten;  the  gluten  paste  contains  the 
greater  part  of  the  insoluble  gluten,  part  of  the  gluten 
starch,  some  raw  starch,  most  of  the  bran  and  nearly 
all  the  soluble  ingredients  of  the  wheat  flour.  The 
raw  starch  is  then  in  the  usual  way  farther  manipulated, 
stirred  up  with  water,  allowed  to  ferment,  and  is  re- 
fined. 

This  method  of  producing  starch  is  in  a  national  eco- 
nomical respect  of  the  highest  importance,  and  espe- 


THE    TECHNOLOGY    OF    STARCH.  115 

cially  since  the  loss  of  valuable  substances  thereby  is 
but  very  insignificant,  and  is  almost  exclusively  con- 
fined to  those  substances  which  are  taken  off  by  the 
edulcorating  (wasting)  water  from  the  raw  starch. 
The  gluten-paste  contains  the  larger  quantity  of  sub- 
stances which,  besides  starch,  are  found  in  wheat. 
In  every  respect  FesccCs  latest  method  excels  all 
others,  as  with  them,  the  soluble  ingredients  of  the 
wheat  (albumen,  gum,  and  salt)  are  almost  entirely 
lost,  while  a  part  of  the  soluble  substance  of  the 
gluten  is  also  lost. 

For  the  pursuit  of  this  method  of  fabrication,  the 
most  suitable  species  of  grain  are  the  semi-hard  or 
medium  soft  kinds  of  wheat.  Neither  from  the  hard 
nor  glassy  (flint-like),  nor  from  the  soft  or  very  mealy 
wheat  species  can  the  production  of  starch  be  effected 
with  equal  success. 

PRODUCING  or  STARCH  ox  A  SMALL  SCALE  FOR 
DOMESTIC  USE. 

In  farmers'  families,  they  frequently  make  the  starch 
needed  for  home  use  themselves.  The  simplest  method 
is  the  following: — 

Take  one  hectolitre  (2.8  bushels)  of  good  wheat, 
which  has  been  freed  of  all  impurities,  place  the  same 
in  a  vessel  of  corresponding  size,  and  pour  as  much 
water  thereon  as  will  cover  it  completely.  After  the 
lapse  of  twenty-four  hours,  the  wheat  is  well  stirred, 
the  water,  after  haying  settled  again,  is  drained  off 
and  replaced  by  fresh  water.  After  the  lapse  of 
another  twenty-four  hours  this  water  is  also  with- 
drawn, and  this  operation  of  changing  the  water  is  con- 
tinued until  the  substance  in  the  wheat  can  be  pressed 


110  MANUFACTURE    OF    STARCH,    ETC. 

out  in  the  form  of  a  thick  milk.  Thereupon  this  milk 
is  pressed  through  a  linen  bag  into  a  clean  vessel. 
This  first  product  is  separately  preserved,  as  it  fur- 
nishes the  finest  aud  purest  starch.  The  residue  re- 
maining in  the  linen  bag  is  mixed  with  water  and  again 
strained;  the  starch  gained  from  this  residue  is  of 
course  of  an  inferior  quality. 

The  first  product  is  given  twenty-four  hours  to  set- 
tle, the  water  above  the  same  is  drained  off  and  sup- 
plied by  fresh  wrater,  and  the  starch  mass  stirred  up, 
repeating  this  after  the  lapse  of  twenty-four  hours. 
As  soon  as  the  water  appears  entirely  clear  and  pure, 
above  the  starch  mass,  a  clean  cloth  is  drawn  over  a 
frame,  and  by  means  of  a  ladle,  the  starch — after  with- 
drawing the  water — is  taken  out  and  left  to  dry  in  the 
open  air. 

Another  still  shorter  method  consists  in  placing  a 
suitable  quantity  of  fine  wheat  flour  in  a  bag  of.  fine 
linen,  tying  the  same  well,  and  kneading  it  beneath  a 
stream  of  water,  which  is  allowed  to  flow  upon  it,  by 
which  operation  the  water  will  carry  off  the  starch, 
while  the  greater  part  of  the  gluten  remains  in  the  bag. 
The  water  thus  impregnated  with  starch  is  filtered 
through  a  silken  sieve,  and  then  manipulated  as  de- 
scribed above.  The  first  water  used  in  kneading  out 
the  starch  can,  after  having  deposited  all  the  starch, 
by  means  of  fermentation,  be  utilized  for  making  a 
pleasant  beverage,  tasting  like  weiss-beer. 

Special  Methods  for  fie  fining  and  Bleaching  of  Wheat 
Starch. — Considering  the  fact  that  the  wheat  starch 
always  retains  greater  or  smaller  quantities  of  gluten, 
which  adhere  mechanically  to  it,  but  the  removal  of 
which,  at  times,  occasions  to  the  manufacturer  great 


THE   TECHNOLOGY    OF    STARCH.  117 

difficulties,  the  most  various  methods  for  refining  and 
bleaching  have  been  proposed.  Some  of  them  we  will 
here  describe. 

E.  Nash  applies  for  the  removing  of  gluten  from  the 
wheat  starch,  ammonia,  as  experience  has  convinced 
him  that  liquid  ammonia  is  the  best  means  of  dissolving 
the  gluten,  also  the  pigment,  and  all  soluble  impurities 
of  the  starch  in  as  far  as  it  exerts  a  powerful  action  on 
the  gluten  and  the  pigment  without  affecting  the  starch. 
Liquid  ammonia  of  0.945  is  of  sufficient  strength,  and 
is  preferable  to  caustic-soda  or  caustic-potash,  since 
the  saturated  solutions  of  the  .same  affect  with  equal 
force  the  starch  and  the  gluten.  The  application  of 
ammonia  has  also  the  advantage  of  extracting  from 
the  starch  the  astringent  substances. 

Ammonia  can  be  used  for  refining  the  starch  in  the 
liquid  (ammonia  water),  or  also  in  gaseous  form.  In 
the  latter  case  it  is  permitted  to  enter  the  vessels 
containing  the  starch  by  means  of  refrigerators.  For 
this  purpose  closed  vessels  are  most  suitable ;  and  for 
accelerating  the  process  the  temperature  of  the  mass 
maybe  increased  without  fear  of  thereby  affecting  the 
starch.  In  most  cases,  however,  an  application  of 
ammonia  will  suffice  to  cover  all  practical  purposes 
without  heating  the  starch.  Based  on  the  expe- 
rience of  Nasli,  ammonia  can  be  recommended  with 
great  advantage  for  conserving  and  improving  all 
flour-containing  substances.  So,  for  instance,  all  in- 
ferior sorts  of  rice,  beans,  and  peas  will  gain  mate- 
rially in  quality  and  taste,  when  they  are,  previous  to 
cooking,  steeped  in  ammonia-water,  and  thereby  freed 
of  their  impurities.  Nash  recommends,  under  all  cir- 
cumstances, to  add  to  the  starch,  prior  to  finishing  the 


118  MANUFACTURE    OF    STARCH,    ETC. 

Samuel  Hall  recommends  for  extracting  the  yellow- 
ish pigment,  the  application  of  chloride  of  lime,  which 
is  diluted  with  water  to  such  a  degree  that  in  100  litres 
(26.4  galls.)  water  1^  kg.  (3.3  Ibs.)  chloride  of  lime  are 
dissolved.  The  starch  is  now,  after  having  been  finished 
to  the  forming  of  cakes  again,  stirred  up  in  water  and 
diluted  to  the  thickness  of  cream,  thereupon  for  each 
kilogramme  (2.2  Ibs.)  of  starch  9  litres  (2.38  galls.)  of 
bleaching  liquid  are  added.  After  all  has  been  well 
stirred  20  litres  (5.28  galls.)  more  water  are  added, 
and  then  the  mixture  is  left  to  settle,  so  that  the  in- 
soluble parts  may  precipitate  to  the  bottom.  In  this 
drained-off  liquor  are  now  poured  133  grammes  (4.66 
ozs.  avoirdupois)  of  sulphuric  acid,  diluted  in  9  litres 
(2.38  galls.)  of  water  for  each  kilogramme  (2.2  Ibs.)  of 
starch ;  after  which  the  same  liquid  is  again  poured 
over  the  starch  in  order  to  cause  the  acid  to  dissolve  all 
foreign  substances,  and  into  this  solution  finally  18  litres 
(4.75  galls.)  more  water  are  poured  for  each  kilogramme 
of  starch.  The  liquid  is  then  permitted  to  rest  a  suffi- 
cient time  in  order  to  allow  the  refined  and  bleached 
starch  to  settle  to  the  bottom.  The  precipitated  starch 
is  thereupon  freed,  by  the  use  of  a  great  deal  of  water, 
from  all  chloride  and  sulphate  of  lime  and  free  acid, 
is  formed  in  cakes  in  the  above  described  manner  and 
afterwards  dried.  • 

Starch  treated  thus  is  very  pure  and  of  great  white- 
ness, laces,  cotton  textiles,  etc.,  starched  therewith 
obtain  a  whiteness  and  gloss  which  they  would  never 
acquire  by  the  use  of  common  starch. 

E.  Tucker  purifies  his  starch  with  a  weak  solution  of 
glauber  salts.  The  proportion  is  for  a  quantity  of 
starch  obtained  from  1000  kg.  (2200  Ibs.),  of  wheat,  6 
kg.  (13.2  Ibs.)  glauber  salts  (sulphate  of  soda). 


THE  TECHNOLOGY  OF  STARCH.         119 

According  to  Martin's  method,  the  impure  starch 
can  be  freed  of  foreign  admixtures  and  a  better  quality 
obtained  by  washing  the  same,  not  only  with  water, 
but  also  by  adding  to  it  some  caustic  soda.  To  this 
end,  the  .first  product  gathered  upon  the  inclined  plane 
is  mixed  with  water  and  a  solution  of  caustic  soda  of 
2°  B.  added  thereto  until  reddened  litmus  paper  turns 
blue  therein.  In  most  cases  a  two  hours'  maceration 
will  be  ample,  and  the  starch  be  freed  from  foreign 
ingredients.  After  the  effect  is  plainly  visible,  this 
solution  is  diluted  with  a  large  quantity  of  water,  per- 
mitted to  pass  through  a  very  fine  hair-sieve,  whereby 
swelled-up  gluten  and  other  foreign  bodies  remain  in 
the  sieve,  while  the  starch  flows  through.  After  a 
brief  interval,  during  which  time  generally  small  por- 
tions of  sand  deposit  themselves,  the  starch-milk  is 
permitted  to  run  over  inclined  planes,  and  in  this 
manner  a  much  larger  yield  of  pure  starch  results, 
than  by  the  common  method  of  washing. 

Kirchhoff  recommends  for  refining  gluten  containing 
wheat-starch  the  following  operation  :  Take  three  parts 
of  potash  and  four  parts  freshly  slaked  lime  to  one 
hundred  parts  of  water,  and  a  caustic  solution  is  thus 
prepared,  of  which  for  each  one  kilogramme  (2.2  Ibs.) 
of  the  starch  one  kilogramme  of  the  solution  is  taken. 
The  whole  js  frequently  stirred  and  left  to  settle  for 
two  or  three  days  in  a  medium  temperature.  There- 
upon, the  starch  is  diligently  washed  in  order  to  free  it 
of  the  adhering  lye. 

Leuchs  proposes  for  the  removal  of  gluten  from 
wheat-starch  in  lieu  of  the  fermenting  process,  the 
extracting  (washing  out)  with  kali-  or  natron-lye,  which 
then,  for  the  purpose  of  bleaching,  is  to  be  saturated 
to  one-sixth  to  one-fourth  with  chlorine. 


120  MANUFACTURE    OF    STARCH,    ETC. 

THE  MANUFACTURE  OF  CORN-STARCH  (MAIZE- 
STARCH). 

Maize  or  Indian  corn  (Zea  mays)  is  a  native  plant 
of  North  America,  but  is  at  present  cultivated  in  all 
warm  climates,  and  is  even  in  lands  of  a  colder  climate 
largely  planted.  The  varieties  of  maize  are  very 
numerous,  exhibiting  every  grade  of  size,  color,  and 
shape,  between  the  shrubby  reed  that  grows  on  the 
shores  of  Lake  Superior  to  the  gigantic  stalk  of  the 
Ohio  valley;  the  tiny  ears  with  flat,  close,  clinging 
grains,  of  Canada;  the  brilliant  rounded  little  pearl, 
or  the  bright  red  grains  and  white  cob  of  the  eight 
rowred  hsemetic,  to  the  swelling  ears  of  the  large  white 
and  yellow  seed  of  the  South.  There  are  something 
like  eleven  principal  varieties  cultivated  in  the  United 
States,  which  may  be  distinguished  by  the  number  of 
rows  of  grains  on  the  cob,  and  the  color,  shape,  or 
size  of  the  kernels. 

"Wherever  maize  is  cultivated  in  large  quantities,  it 
is  not  only  used  for  distilling  high  wines,  but  princi- 
pally for  producing  starch,  and  as  food  for  man  and 
beast.  As  is  the  case  with  wheat,  so  also  maize  varies 
as  to  the  composition  of  its  grains,  according  to  climate 
and  soil.  In  general,  it  may  be  asserted,  that  the  con- 
tents of  starch  in  maize  fluctuate  between  50  and  60 
per  cent.,  as  the  result  of  the  following  analyses  will 
show : — 


THE    TECHNOLOGY    OF    STARCH. 


121 


Composition  of  100  weight 
parts  maize  according  to 

Maize  flour 
(corn  meal) 

according  to 

R.Fresenius. 

Poggiale. 

Stepf. 

Water    . 

13.46 

13.5 

10.60 

Fat 

5.11 

6.7 

3.80 

Gum  (dextrine) 

2.33 

3.05 

Sugar    . 

.... 

371 

Albumen 

.... 

.... 

061 

Protein  generally 

10.04 

0.9 

6.71 

Starch   . 

65.90 

64.5 

71.52 

Fibrin    . 

1.58 

4.0 

.... 

Ashy  ingredients 

1.58 

1.4 

100.00 


100.0 


100.00 


From  the  following  Table  the  composition  of  the  various  species 
of  corn  can  be  learned. 


American  maize. 


Percentage  composition. 

Flat  white. 

Flat  yellow. 

Round  yel- 
low. 

Water    .... 

11.8 

11.5 

13.2 

Starch    .... 

54.8 

53.5 

54.8 

Cellulose 

15.9 

16.5 

14.9 

Starch,  cellulose,  and  loss 

..... 

.... 

.... 

Gum      .... 

.... 

.... 

.... 

Sugar     .... 

.  ••  .  . 

.... 

.  .   . 

Gum  and  sugar 

2.9 

2.3 

2.9 

Fat 

4.4 

4.7 

4.4 

Extractive  substances  . 

.... 

.... 

.... 

Pi.srment 

Albumen 

.... 

.... 

Soluble  albuminates      .... 

Insoluble  albuminates  .... 



.... 

.  .  !  . 

Gluten  . 

'*89 

8.7 

*8  9 

Ashes    

1.8 

1.6 

1.8 

100.5 

98.8 

1C0.9 

Respecting  its  anatomical  structure  and  its  qualita- 
tive chemical  condition  maize  is  very  similar  to  wheat; 
from  this  it  follows  that  the  method  of  separating  the 
starch  from  the  maize  does  not  essentially  differ  from 
that  used  with  wheat.  But  inasmuch  as  the  gluten  of 
the  maize  does  not  form  such  a  tough  mass  as  the 
wheat  gluten,  it  is  not  necessary  to  soften  and  dissolve 


122  MANUFACTURE    OF    STARCH,    ETC. 

it  by  fermentation,  but  the  fermenting  process  is 
omitted,  and  hence  we  can  always  obtain  the  gluten  as 
an  excellent  food  for  domestic  animals. 

The  first  experiments  in  making  corn-starch  were 
made  in  America  and  England.  The  Indian  corn 
(maize)  is,  after  a  previous  cleaning  of  adhering 
dross,  steeped  in  water  for  a  period  of  from  24  to  30 
hours,  thereupon  bruised  between  rollers,  or  under 
horizontally  moving  burr-stones  ground  into  a,  fine 
paste.  The  ground  (milled)  corn  is  then  washed  out 
in  cylinder-sieves  (as  we  have  already  described),  i.  e., 
separated  into  hulls  and  starch- milk.  The  latter  is 
placed  upon  inclined  planes,  where  the  starch-granules 
deposit  themselves,  while  the  lighter  gluten  and  fibrin 
substances  are  gathered  in  large  tanks.  After  the 
water  has  become  clear,  and  the  suspended  sub- 
stances have  in  greater  part  deposited  themselves,  the 
water  is  drained  off,  and  the  entire  deposit  thus  gained, 
together  with  the  hulls  which  have  remained  in  the 
cylinder-sieves,  are  used  for  fodder,  which  thus  pro- 
duced is  rich  in  azotic  nutritious  substances,  fats,  and 
mineral  substances,  and  hence  of  great  value  as  feed. 

The  starch  deposited  in  the  gutters  is  not  yet  en- 
tirely free  from  azotic  ingredients,  but  already  in  this 
condition  forms  an  excellent  article  for  finishing  tex- 
tiles, since  it  furnishes  a  good  paste. 

For  manufacturing  a  finer  quality,  the  starch  is 
taken  from  the  gutters,  and  the  gluten  contained 
therein  is  dissolved  by  treating  it  with  alkaline  solu- 
tions. By  a  further  extended  washing  in  finer  sieves, 
the  maize  starch  can  be  obtained  in  a  perfectly  pure 
condition. 

Inasmuch  as  the  gluten  of  maize  is  not  by  far  so 
tough  a  substance  as  wheat  gluten,  it  need  never  be 


THE   TECHNOLOGY    OF    STARCH.  123 

dissolved  by  fermenting,  and  the  process  of  fermenta- 
tion is  generally  dispensed  with,  in  order  to  obtain 
a  better  and  more  valuable  food  for  cattle  and  hogs. 
Notwithstanding  this,  however,  Watts  uses,  by  his 
method  of  manufacturing  corn-starch,  a  slight  fer- 
mentation. He  leaves  the  maize  to  steep  in  a  tem- 
perature of  from  25  to  60°  C.  (77  to  140°  F.)  until  a 
gentle  fermentation  ensues.  The  maize  is  thereupon 
freed  from  the  liquid  above,  crushed  (bruised)  and 
washed  out  with  water. 

By  Ijeconte's  latest  method,  maize-starch  is  pre- 
pared in  such  a  manner  that  the  corn  is  soaked  in  a 
solution  of  caustic  soda,  and  after  washing  in  a  wire- 
sieve,  is  bruised  between  millstones,  over  which 
water  is  allowed  to  stream.  The  starch-milk  thus  ob- 
tained is  conducted  through  sieves  over  inclined 
planes,  on  which  the  starch  is  deposited,  while  the 
greater  part  of  the  fibres  remain  in  the  sieve. 

In  order  to  cause  a  more  perfect  separation  of  starch 
from  the  maize,  sulphurous  acid  has  been  applied 
with  favorable  results  in  modern  times,  and  the  follow- 
ing directions  for  making  starch  from  maize  can  be 
relied  on: — 

The  maize  is,  according  to  its  quality  and  the  tem- 
perature prevalent,  steeped  during  a  period  of  from  12 
to  48  hours  in  fresh  wrater,  the  same  being  frequently 
renewed,  whereby  the  maize  attains  a  very  extraordi- 
nary degree  of  toughness,  but  at  the  same  time  all 
adhering  dross  and  clay-parts  are  softened. 

After  a  sufficiently  long  steeping  the  maize  is 
washed,  \vhile  a  constant  flow  of  water  over  it  is  main- 
tained. For  manufacturing  corn-starch  on  a  large 
scale  an  extra  stirring  apparatus  is  used,  somewhat 
similar  to  the  one  for  the  mashing  of  grain.  The 


124  MANUFACTURE    OF    STARCH,    ETC. 

cleansed  maize  is  then  bruised,  for  which  operation  a 
crushing  roller,  composed  of  three  pairs  of  rollers,  is 
the  most  suitable.  This  roller  apparatus  is  con- 
structed as  follows:  the  first  pair  of  rollers  consists  of 
extra-hard  iron  or  steel  rollers,  whose  task  is  the  first 
breaking  up  or  crushing  of  the  maize.  The  second  set 
of  rollers  is  made  of  hard  iron,  and  are  perfectly  smooth, 
and  hence  suited  to  grind  the  maize  fine.  The  third 
roller  pair  consists  of  cast-iron  rollers,  and  they  com- 
plete the  grinding  to  a  fine  paste. 

The  maize  thus  bruised  to  the  fineness  of  common 
flour  is  then  placed  in  large  vats  of  from  1  to  1.25 
cubic  metres  (1.3  to  1.63  cubic  yards),  or  from  10  to 
12  hectolitres  (28  to  33.6  bushels)  capacity.  There- 
upon it  is  mixed  with  water  containing  some  sulphuric 
acid  gas,  and  then  left  at  rest  for  a  period  of  from  six 
to  twelve  hours,  during  which  time  the  starch  granules 
are  being  entirely  laid  bare. 

The  maize  paste  treated  in  the  manner  described,  by 
which  the  starch  is  almost  perfectly  separated  from 
the  cellulose,  is  finally  washed  out  by  applying  the 
well-known  cylinder  sieves,  and  the  raw  starch  ob- 
tained is  refined  upon  inclined  gutters. 

The  largest  establishments  for  the  manufacture  of 
starch  from  maize  exist  at  present  in  the  United  States 
and  England. 

A  description  of  A.  Erkenbr edicts  celebrated  estab- 
lishment in  Cincinnati,  Ohio,  will  doubtless  be  of  great 
interest  to  the  reader,  as  by  it  the  magnitude  of  this 
traffic  and  industry  may  be  set  forth.  The  raw  mate- 
rial— the  Indian  corn  on  the  cob — arrives  by  ship  or 
railroad  car  directly  at  the  gates  of  this  most  extensive 
corn-starch  manufactory  in  America.  The  corn  is 
then  by  an  elevator  lifted  on  to  scales  and,  after  a  cer- 


THE    TECHNOLOGY    OF    STARCH.  125 

tain  weight  having  been  loaded  on,  the  elevator  bottom 
is  opened,  whereby  the  maize  is  caused  to  descend  to 
a  cellar.  Here  it  is  received  at  once  on  another  eleva- 
tor which  carries  it  up  to  the  fourth  story  to  the  grain 
extracting  and  separating  machines.  The  loosened 
grain  is  then  transmitted  directly  to  the  subterraneous 
fermenting  tubs,  of  which  there  are  25  of  700  bushels 
capacity  each.  All  the  vats  and  basins  are  made  of 
marble — not  of  wood.  Meantime  another  elevator 
carries  the  cobs,  now  freed  of  corn,  120  metres  (131 
yards)  distance  into  the  coal  bunkers,  where  they  are 
mixed  with  anthracite  coal  and  used  as  fuel,  furnish- 
ing an  extraordinarily  intense  heat.  The  corn  re- 
mains in  the  vats,  filled  with  water,  from  thirty-six 
to  forty  hours,  during  which  time,  on  account  of  the 
ensuing  of  some  fermentation,  the  gluten  is  dissolved. 
The  corn  is  then  placed  in  a  moist  state  between  burr- 
stones  while  water  is  pouring  over  it.  The  paste  thus 
obtained  is  ground  still  finer  in  another  pair  of  rollers, 
and  receives  at  the  same  time  an  additional  supply  of 
water.  In  the  tanks  (basins)  where  the  paste  is  gath- 
ered, the  starch  precipitates  to  the  bottom  while  the 
foreign  ingredients  floating  on  the  surface,  such  as 
gluten,  hull  fragments,  etc.,  are  drawn  off,  and  being 
loaded  on  wagons,  which  are  in  waiting,  are  carried 
away  to  be  disposed  of  as  feed  for  cattle,  etc.  The 
starch  is  frequently  stirred,  and  flows  into  a  system 
of  channels  of  about  30  metres  (33  yards)  in  length, 
and  30  centimetres  (11.8  inches)  in  width,  and  19 
centimetres  (7.5  inches)  in  depth,  where  its  thorough 
washing  is  effected.  After  the  starch  again  deposits 
itself,  it  is  dug  out  (the  first  manual  labor),  and  is  then 
taken  in  a  moist  condition  to  an  elevator  which  carries 
the  starch  to  the  drying-rooms.  Here  it  is  first  placed 


126  MANUFACTURE   OF    STARCH,    ETC. 

upon  warmed  bricks  and  slowly  dried,  then  wrapped 
up  in  paper,  and  by  exposure  to  an  increased  heat 
completely  dried. 

The  paste  of  maize-starch  is,  as  is  well  known, 
noted  for  its  great  power  of  stiffening,  and  the  blend- 
ing whiteness,  smooth  appearance,  and  gloss  of  Ameri- 
can linen  is  the  result  of  the  use  of  maize-starch. 

The  celebrated  and  extensive  establishment  of  the 
Glen  Cove  Company  in  the  State  of  New  York,  uses 
the  white  species  of  maize  from  the  Southern  and  Cen- 
tral States,  for  the  production  of  two  kinds  of  starch. 
The  finer  quality,  "  DuryecCs  Maizena"  appears  in  the 
market  in  the  form  of  a  white  powder,  the  second  quality 
is  found  in  commerce  as  starch  in  pieces,  similar  to  our 
wheat-starch.  The  former,  the  maizena,  being  cheaper 
than  any  kind  of  arrowroot,  and  in  quality  not  inferior, 
is  frequently  used  as  a  substitute  for  the  latter. 

Maizena  is  prepared  in  this  establishment  from  the 
farinaceous  parts;  the  common  starch,  however,  from 
the  Horny  parts  of  the  maize  grains,  but  the  method 
used  is  not  known  to  us. 

From  maizena  most  excellent  biscuits  are  made  by 
the  celebrated  British  firm,  Huntley  &  Palmer  (9  Road 
Lane,  London,  and 'Reading,  Berkshire  Co.). 

The  corn-starch  manufactory  of  Brown  &  Poison, 
in  Paisley,  Scotland,  is  among  the  most  gigantic 
establishments  of  the  kind.  Their  fabrication  is 
brought  into  the  traffic  under  the  name  "  Brown  & 
Poison's  Corn-flour"  in  packages  of  various  sizes. 

Besides  North  America  and  England,  corn-starch 
is  also  manufactured  in  South  America,  especially  in 
Brazil ;  furthermore,  in  New  South  Wales  (Australia), 
and  in  France  and  Hungary. 


THE   TECHNOLOGY    OF    STARCH.  127 

Corn-starch  is  not  only  used  for  industrial  and  tech- 
nical purposes,  but  also  as  a  dietic  food. 

THE  MANUFACTURE  OF  RICE-STARCH. 

~R\ce(Oriza  sativa*)is  the  principal  plant  of  culture 
and  the  chief  means  of  subsistence  for  southern  cli- 
mates. The  grain  is  of  Asiatic  origin.  From  the 
earliest  records  it  has  formed  the  principal,  if  not 
indeed  the  only  food  of  a  large  proportion  of  the  popu- 
lation of  India  and  throughout  the  Chinese  Empire. 
In  Europe  it  is  cultivated  in  Italy  and  Spain,  while 
in  America,  Brazil  and  the  Southern  States  of  the 
American  Union  produce  it  in  large  quantities.  The 
culture  of  rice  depends  besides  the  warmth  of  the 
climate,  principally  on  the  fact,  that  the  soil  planted 
with  rice  can  alternately  be  placed  under  water  (sub- 
.merged)  for  an  extended  period.  The  rice  districts 
therefore  form  extensive  fields  of  ground,  which  if 

*  The  following  analysis  of  rice  is  by  Payen.  Air-dry  rice 
contains: — 

Starch 86.9 

Gluten .        .  7.5 

Fatty  matter 0.8 

Gum 0.5 

Epidermis 3.4 

Ash 0.9 

Total 100.0 

The  ashes  of  rice  have  been  analyzed  with  the  following  results: — 

Grain.  Husk. 

Potash 18.48  1.60 

Soda 10.67  1.58 

Magnesia 11.69  1.96 

Lime 1.27  1.01 

Phosphoric  acid 53.36  1.86 

Silica 3.35  89.71 

Peroxide  of  iron  0.45  0.54 


128  MANUFACTURE    OF    STARCH,    ETC. 

necessary  can  be  submerged.  Rice  is  not  a  very 
nourishing  food,  and  a  population  depending  on  this 
cereal  for  its  maintenance  requires  large  quantities 
thereof  to  satisfy  its  wants.  On  the  other  hand,  rice 
excels  all  other  cereals  by  its  contents  of  starch,  hence, 
it  is  very  suitable  for  the  manufacture  of  starch,  espe- 
cially in  those  countries  where  it  is  raised. 

In  its  air-dry  state  the  contents  of  starch  vary  from 
70  to  75  per  cent.  The  following  analyses  of  the  rice 
grain  are  by  Pay  en  : — 

I.  II.  in. 

Water 12.51  14.6 

Starch 74.88  >  ?6  Q  g6  9 

Dextrine 1.11  > 

Sugar         .....  traces  .....  traces 

Fat 0.78  0.5  0.8 

Cellulose 0.76  0.9  4.3 

Soluble  albuminates  .         .  0.41  >  „  ~  ^  ^ 

Insoluble  albuminates        .         .  8.78  > 

Extractive  matter     .         .         .011                .... 

Ashes 0.84  0.5  0.5 

100.18  100.0  100.0 

None  of  all  the  raw  materials  that  have  hitherto 
been  applied  for  manufacturing  starch,  is  as  rich  in 
starch  as  rice.  The  single  cells  of  the  rice  grains, 
and  in  these  the  single  starch  granules,  are  so  firmly 
put  together  one  with  another,  that  the  separation  of 
the  starch  from  the  other  ingredients  (fibrin,  gluti- 
nous matter  with  some  albumen,  gum,  mucilaginous 
sugar,  fatty  oils,  and  alkalies)  will  not  be  effected  by 
the  mere  process  of  steeping  and  bruising.  This  diffi- 
culty, however,  may  be  completely  overcome  by  the 
application  of  caustic  potash  or  caustic  soda  lyes. 

The  inventor  of  this  process  of  manufacturing  starch, 
especially  from  rice,  is  Orlando  Jones,  who  furnishes 


THE    TECHNOLOGY    OF    STARCH.  129 

for  the  carrying  out  of  this  method  the  following 
accurate  directions: — 

A  caustic  lye  is  prepared  of  potash  or  soda  with 
lime  in  the  usual  way,  and  the  percent um  contents  of 
the  same  of  anhydrous  alkali  are  determined  by  the 
alkalimetric  way  (by  neutralization  of  a  certain  quan- 
tity with  sulphuric  acid)  ;  thereupon  the  l}Te  is  diluted 
by  adding  pure  water,  so  that  one  part  of  alkali  is 
contained  in  three  hundred  and  fifty  parts  of  water. 
In  five  hundred  parts  of  such  a  diluted  lye,  one  hun- 
dred parts  of  rice  are  steeped,  best  in  a  copper  vessel 
or  in  iron  lined  with  tin.  On  one  side  of  the  bottom 
of  this  vessel  a  tin  cock  is  placed,  whose  inner  muzzle 
is  covered  with  a  finely  perforated  plate,  by  which 
the  rice  is  retained  when  the  lye  is  being  drained 
off.  After  twenty-four  hours'  steeping  the  liquid  is 
drawn  off  by  the  use  of  the  cock,  and  when  thus  with- 
drawn is  replaced  by  a  double  quantity  of  pure  water, 
wherein  the  rice  must  be  well  stirred,  and  then  the- 
water  is  drained  off  again  in  the  same  manner  as 
before.  The  rice  thus  cleaned  is  put  into  sieves  ta 
drain  off  all  moisture,  then  ground  between  the  two 
rollers  of  a  crusher  or  the  stones  of  a  common  mill,, 
and  it  is  then  by  the  aid  of  brushes  pressed  through 
sieves.  The  coarser  parts  of  the  rice  not  having 
passed  through  the  sieve  are  again  ground  and  put 
through  it.  This  operation  is  repeated  until  finally 
only  a  small  residue  of  bran  remains,  which  is  of  no 
use. 

The  flour  thus  obtained  is  carefully  stirred  in  a 
tin-lined  iron  or  copper  vessel  with  the  tenfold  quan- 
tity of  the  above  described  alkaline  solution,  adding 
thereto  the  substance,  which  may  have  precipitated 
from  the  water  used  in  steeping  the  whole  rice  grain. 


130  MANUFACTURE    OF    STARCH,    ETC. 

The  mass  is  then  almost  uninterruptedly  stirred  for 
twenty  four  hours,  whereby  the  action  of  the  lye  is 
augmented,  but  finally  it  is  left  to  settle  for  about 
seventy  hours.  During  this  resting  in  the  first  place 
the  heavier  substances,  mineral  impurities,  sand,  etc. 
precipitate,  above  this  layer  the  coarser  parts  of 
crushed  hulls  deposit  themselves,  while  the  pure 
starch  forms  the  upper  layer.  The  brownish-yellow, 
muddy  liquid  which  forms  on  the  surface,  contains 
the  dissolved  gluten.  After  being  convinced  that  no 
further  settling  is  taking  place,  this  liquid  gluten  is 
drawn  off  with  great  care  by  applying  a  tin  siphon, 
without  stirring  up  the  sediment.  Finally  this  sedi- 
ment is  mixed  with  double  the  quantity  of  water  as  of 
the  lye  solution  previously  used.  This  having  been 
attended  to,  the  mass  is  permitted  to  rest  for  one 
hour,  to  allow  the  heavy  fibrous  parts  to  precipitate, 
while  the  starch  is  still  suspended.  The  starch  con- 
taining milky  liquid  is  then — by  means  of  the  siphon 
— poured  through  a  series  of  silken  sieves,  whereby 
the  fibres  and  foreign  ingredients  are  kept  back,  while 
the  starch  containing  liquid  runs  into  large  vats. 

The  impurities  deposited  in  the  first  vat,  still  con- 
taining much  starch,  are  mixed  with  water,  and  the 
same  process  is  repeated  as  before,  in  order  to  free  the 
starch  as  much  as  possible  from  the  fibrous  substances. 
By  repeated  depositing  and  decanting,  whereby  the 
liquid  is  always  strained  through  fine  sieves,  new  por- 
tions of  pure  starch-milk  are  gained,  which  are,  as  a 
rule,  added  to  the  first  milky  liquid. 

In  the  large  depositing  vats,  which  hold  the  refined 
starch-milk,  the  pure  starch  precipitates  thoroughly 
within  seventy  hours.  It  is  perhaps  once  more  washed 
with  fresh  water,  and  thereupon  placed  in  baskets  or 


THE   TECHNOLOGY    OF   STARCH.  131 

bags  to  let  the  water  drop  off,  and  finally  dried  in  the 
same  manner  as  wheat-starch. 

The  bleaching  of  the  rice-starch  usually  takes  place 
prior  to  the  drying. 

H.  Ransford  applies  an  alkaline  liquid  for  the  fabri- 
cation of  starch  from  rice,  in  which  he  soaks  the  rice  in 
order  to  dissolve  the  albuminous  parts  contained  therein. 
Instead  of  permitting  the  liquid — as  Jones  does  by 
his  method — to  rest  with  the  rice,  Ransford  keeps  it 
in  motion.  This  is  done,  either  by  letting  the  solution 
of  lye  run  out  from-  the  top  of  the  tank,  and  by  means 
of  a  pump  forcing  it  back  in  the  lower  part  through  a 
perforated  bottom,  or  using  for  this  operation  a  tight 
tank,  in  which  by  means  of  a  pump  the  alkaline  liquid 
is  forced  in,  until  a  pressure  of  20  pounds  per  square 
inch  is  caused  inside  of  the  tank.  This  operation  is 
repeated  with  a  renewed  supply  of  lye,  after  previously 
draining  off  a  part  of  the  liquor.  When  the  rice  is 
perfectly  saturated  by  the  lye,  it  is  taken  out  therefrom, 
and  to  remove  the  gluten  the  substance  is  placed  in 
bags  of  suitable  texture  and  subjected  to  pressure, 
whereupon  it  is  ground  fine  and  then  manipulated  for 
obtaining  the  starch,  as  set  forth  above.  To  free  the 
starch  obtained  from  rice,  of  its  water,  Ransford  recom- 
mends the  use  of  flat  metal  vessels  (boxes),  with  per- 
forated bottoms.  These  boxes  are,  by  partitions  made 
of  plated  zinc,  divided  into  sections,  and  so  arranged, 
that,  from  the  space  beneath  the  perforated  bottom,  the 
air  can  be  pumped  out.  The  perforated  bottom  of  the 
vessel  is  covered  with  a  thick  cloth.  The  starch,  ap- 
pearing usually  mixed  with  some  pigment,  is,  after 
the  water  has  been  drawn  off,  placed  in  the  vessel,  and 
underneath  the  same  a  vacuum  is  produced  by  the  ap- 
plication of  an  air-pump.  By  the  outer  pressure  of  air, 


132  MANUFACTURE    OF    STARCH,    ETC. 

the  greater  part  of  the  water  contained  in  the  starch, 
along  with  the  albuminates  which  may  still  be  con- 
tained therein,  is  pressed  through  the  perforated  bottom 
into  the  lower  part  of  the  box.  By  the  partitions  of 
these  boxes,  the  dried  starch  receives  a  similar  shape, 
as  is  the  case  in  the  much  used  filter  boxes,  that  is,  the 
starch  forms  in  long  bars.  These  are  cut  up  into 
smaller  pieces  and  dried  in  the  well-known  manner. 

Berger's  treatment  is  similar  to  the  method  of  Jones. 
100  kilogrammes  (220  pounds)  of  rice  are  steeped  for 
two  days  in  water,  then  ground  and  mixed  with  suffi- 
cient water  to  form  a  milky  liquid,  then  poured  through 
a  sieve  with  8|  openings  to  the  square  centimetre  (0.155 
sq.  inch).  Those  parts  of  the  rice  which  do  not  pass 
through  the  sieve  are  again  placed  in  the  mill  to  be 
reground.  The  milky  liquid  is  then  mixed  with  a  so- 
lution of  7.5  kilogrammes  (16.5  pounds)  of  carbonate 
of  soda  in  5  parts  of  water,  permitted  to  settle  for  four 
hours  and  again  stirred.  This  operation  is  repeated 
until  the  rice  has  been  at  least  60  hours  in  contact  with 
the  alkaline  liquid.  The  mass  is  then  left  to  rest  for  18 
hours.  During  this  period,  the  starch  precipitates  to 
the  bottom,  while  the  greater  part  of  the  gluten  and 
other  foreign  ingredients  dissolves,  and  is  removed 
by  a  siphon.  This  treatment  with  soda  lye  is  again 
repeated,  in  order  completely  to  remove  the  soluble  in- 
gredients of  the  rice.  Thereupon  follows  the  process  of 
washing,  as  in  Jones's  method,  for  removing  the  sand 
and  other  foreign  admixtures,  and  finally  the  pure 
starch  thus  gained  is  repeatedly  washed  out  in  water 
and  dried. 

Berger  also  produces  rice-starch  by  the  process  of 
fermentation,  in  this  manner:  The  rice  is  left  to  steep 
from  five  to  six  days,  then  ground,  the  flour  mixed 


THE    TECHNOLOGY    OF   STARCH.  133 

with  water,  and  this  left  to  ferment  so  long  that  the 
gluten  is  in  such  a  condition  that  it  can  be  removed 
by  washing  it  out.  But  this  method  is  not  much  used. 

A  similar  process  is  that  of  Colman,  by  which  for 
every  100  weight  parts  of  rice-flour  mixed  with  water, 
15  weight  parts  of  the  sour  residue  obtained  during  the 
operation  in  the  pressing  of  wheat-starch,  are  mixed. 
The  fermentation  process  is,  as  becomes  evident,  very 
much  advanced  thereby. 

The  American  method  of  obtaining  starch  from  rice 
is  as  follows:  The  rice  is  steeped  in  wooden  boxes  or 
vats  with  a  caustic  soda  lye  of  1.75°  B.,  and  remains 
therein  for  eighteen  hours,  while  being  frequently 
stirred.  The  dirty,  yellowish  lye  is  then  withdrawn; 
passed  through  a  long,  flat,  but  little  inclined  channel 
or  gutter,  upon  which  a  starch  containing  mucus  set- 
tles. The  further  manipulation  of  this  mucus,  as  well 
as  that  of  the  lye,  will  be  described  anon. 

The  rice,  which  must  be  so  soft  that  a  sample  thereof 
can  be  easily  bruised  between  the  fingers,  is  repeatedly 
washed  out  with  water,  and  under  a  stream  of  greatly 
diluted  caustic  soda  lye,  ground  into  a  thin  paste. 
This  paste  is  transmitted  from  the  mill  to  the  flour-vat, 
whose  stirring  apparatus  remains  running  for  the  space 
of  six  hours.  After  the  lapse  of  this  time  the  mass  is 
allowed  to  rest  for  twelve  hours,  whereby,  on  the  one 
hand,  a  more  perfect  loosening  of  the  gluten  is  effected, 
and  otherwise  a  thickening  of  the  mass  by  the  separa- 
tion of  clear  lye  results,  which  latter  is  removed  by 
application  of  a  siphon.  The  thick  paste  is  thereupon 
by  means  of  the  raw-starch  centrifugal  apparatus 
"hurled,"  the  drum  being  filled  to  two-thirds  of  its 
capacity  with  rice-paste,  and  for  fifteen  minutes  kept 
in  rotation.  After  the  drum  is  brought  to  a  halt,  the 


134  MAKUFACTUHE    OF    STARCH,    ETC. 

dirty,  yellowish  alkaline  gluten  solution  of  course  ac- 
cumulates on  the  bottom  of  the  same,  and  can  be  drawn 
out  by  opening  the  holes  in  the  bottom  which  had  been 
closed  during  the  act  of  "hurling."  The  further  use 
of  this  lye,  and  of  the  gluten-starch,  will  be  defined 
below,  and  we  here  only  state  that  the  drained-off 
liquid  may  be  again  used  for  steeping  new  lots  of  rice. 

Corresponding  to  the  various  specific  weights  of  its 
ingredients  a  sharp  line  of  division  of  the  paste  appears 
in  the  apparatus.  Closely  to  the  sides  of  the  drum  the 
white  raw  starch  hangs,  and  on  this  the  grayish-white 
gluten-starch. 

The  buildings  used  by  the  American  rice-starch 
manufacturers  have,  besides  the  basement,  usually 
three  more  stories.  The  white,  solid  raw  starch  is 
usually  taken  from  the  centrifugal  machine  in  the 
basement,  and  by  means  of  an  elevator  hoisted  into  the 
third  story,  and  put  into  the  stirring  vat  in  order  there 
to  be  stirred  up  in  a  w^eak  alkaline  solution.  After 
effecting  a  thorough  mixing,  the  starch-milk  is  passed 
through  a  cylinder  sieve,  of  known  construction,  into 
the  washing-out  vats  of  the  second  stoiy,  where  the 
further  refining  of  the  liquid,  which  has  been  allowed 
to  settle  for  a  short  time,  takes  place.  The  starch-milk 
is  now  drained  off  and  flows  into  the  depositing  vat  on 
the  ground  floor.  Another  straining  will  in  most  cases 
not  be  necessary,  but  it  is  imperative  to  make  the 
necessary  arrangement  which,  however,  has  not  to 
serve  merely  for  this  purpose  alone. 

In  the  depositing  vat,  last  mentioned,  the  starch  is 
allowed  to  settle  until  it  is  deposited  perfectly  firm ; 
the  period  in  which  to  effect  this  is  from  twenty-four  to 
thirty-six  hours.  After  this  is  accomplished,  the  clear 
liquid  is  drawn  off,  the  stirring  up  with  some  water  is 


THE   TECHNOLOGY    OF    STARCH.  135 

repeated,  and  the  starch  is  refined  in  the  centrifugals 
which  are  placed  in  the  basement.  It  is,  however, 
according  to  the  experience  of  some  experts,  not  at  all 
profitable  to  use  the  refining  centrifugal  apparatus, 
although  it  furnishes  the  starch  almost  entirely  air- 
dry,  because  the  pieces  acquire  after  drying  a  peculiar 
rough  surface  when  broken  up,  and  do  not  suit  for  the 
manufacture  of  crystal  starch  on  account  of  their 
form.  A  further  cause  is,  that  the  light  dross,  ^hich 
is  sometimes  suspended  in  the  lye  solution,  is  forced 
together  through  the  whole  starch  cake  to  the  outer 
line,  whereby  portions  of  the  dross  be  ome  mixed  in 
with  the  starch.  Hence  the  latter  loses  at|  least  its 
even  appearance.  For  this  reason  it  would  be  best 
to  use,  for  the  final  process  of  refining,  the  centrifugal 
apparatus  with  closed  sides,  by  which  the  gluten  and' 
dross  remain  in  the  middle  and  can  be  easily  re- 
moved. The  removal  of  these  impurities  is  effected 
by  careful  washing,  and  with  the  aid  of  a  soft  brush, 
and  the  starch  may  now  be  placed  in  the  filling  boxes. 
To  insure  the  evenness  of  the  product  it  is  necessary 
again  to  place  such  piec:s  in  a  vat,  which  is  placed 
at  an  equal  height  with  the  above-mentioned  one 
in  the  second  story  of  the  building.  Here  the  mass 
should  be  stirred  while  adding  water  enough  to  make 
a  thin  milk,  and  finally  passed  through  the  reserve- 
cylinder  sieve  into  boxes  lined  with  dense  cloth. 

In  order  to  simplify  the  filling  of  the  boxes,  the 
following  method  should  be  observed.  The  perforated 
filling  boxes  of  1.25  metres  (4.1  feet)  in  length  and 
lined  smoothly  with  linen  cloth,  are  placed  on  wooden 
frames  in  the  basement  of  the  factory.  The  bottoms  of 
these  frames  are,  towards  the  centre,  gutter-like  deep- 
ened and  lined  with  tin.  The  surplus  starch-milk 


136  MANUFACTURE    OF    STARCH,    ETC. 

must  therefore  run  there  and  can  be  conducted  to  a 
lower  floor.  The  projecting  end  of  each  cloth  is  put 
over  the  rim  of  the  adjacent  box.  The  rims  of  the 
boxes  forming  the  sides  are  raised  5  centimetres  (1.97 
inches).  The  ends  of  the  cloth  are  thrown  across 
lathes  in  such  way  as  the  direction  of  the  flowing 
starch-milk  requires.  If  the  latter  is  now  permitted 
to  run  in  on  one  side,  it  will  enter  from  the  first  box 
into  the  second,  and  so  on  until  the  entire  set  of  boxes 
is  filled  in  succession. 

The  further  manipulation  of  these  pieces,  particu- 
larly suited  for  producing  crystal  starch,  is  essentially 
the  same,  as  the  one  already  defined.  The  residue 
which  remains  in  the  separating  vat  (in  the  second 
story)  consists  in  greater  part  of  gluten-starch  with 
cellulose  hulls  and  not  sufficiently  bruised  particles  of 
rice.  It  is  stirred  up  in  water  and  allowed  to  flow 
through  the  cylinder  sieve  into  a  vat  stationed  on  the 
first  floor,  where  the  process  of  fermentation  takes 
place,  while  the  pieces  of  rice  are  kept  for  regrinding. 

A  similar  manipulation  is  customary  with  the  so- 
called  "  third  product"  being  the  substance  scraped 
from  the  centrifugal  apparatus  after  the  first  operation. 
It  is  brought  by  an  elevator  into  the  second  story,  and 
placed  in  a  Vat,  stirred  with  water,  and  flows  also 
through  the  cylinder  sieve  into  the  above-mentioned 
fermenting  vat  on  the  first  floor.  After  a  thorough 
edulcorating,  the  fermenting  is  brought  on  by  means 
of  putrefied  wheat  gluten.  The  fermentation,  being 
at  first  of  an  alcoholic  nature,  is  soon  transformed  into 
the  acetic  fermentation,  whereby  the  solution  of  the 
gluten  ensues.  After  the  fermentation  is  complete  the 
treatment  is  tiie  same  as  already  described. 


THE    TECHNOLOGY    OF    STARCH.  137 

It  is  necessary  that  the  rooms  used  for  fermenting 
should  form  separate  apartments,  and  not  be  con- 
nected with  those  where  the  fermenting  must  be 
avoided.  The  diverse  vats  may  be  on  the  same  floor 
with  the  steeping  tubs,  but  also  separated  from  these. 
The  easy  introduction  of  warmth  is  of  course  desira- 
ble. The  principle  of  a  terrace-like  order  for  the  whole 
establishment  requires,  that  the  steeping  tubs  be  placed 
above  the  mill,  and  the  receiving  vats  above  the  cen- 
trifugal machines.  If  the  height  of  the  latter  appa- 
ratus (situated  in  the  basement)  is  inclusive  -of  the 
brick  beds  1.4  metre  (4.6  feet),  the  declivity  from  the 
bottom  of  the  receiving  vats  to  the  centrifugal  machine 
and  likewise  from  the  overflow  of  the  mill  to  the 
receiving  vats  each  0.3  metre  (0.98  foot),  then  that  out- 
let must  have  a  height  of  3  metres  (9.84  feet)  from  the 
basement. 

Sulphurous  acid  is,  when  well  prepared,  the  best 
means  of  suppressing  putrefaction.  The  same  eifect 
is  produced  by  sulphite  of  soda,  while  a  calcium  salt 
may  be  applied  in  cases  where  a  formation  of  gypsum 
no  longer  works  injury. 

The  weak  solution  of  lye  which  flows  out  from  the 
centrifugal  machine  during  the  first  operation  can  be 
again  used  for  a  renewed  steeping  of  rice.  In  this 
case  its  contents  of  caustic  soda  are  analyzed,  and  any 
percentage  needed  is  added  by  a  supply  of  fresh  lye. 
In  conclusion  we  will  yet  mention  a  method  invented 
by  Rehe.  According  to  this,  the  rice  is  prior  to  steep- 
ing heated  to  from  60°  to  70°  C.  (to  140°-158°  F.). 
Then  it  is  steeped,  ground,  and,  in  order  to  dissolve 
the  gluten,  it  is  treated  with  8  kilogrammes  (17.6  Ibs.) 
of  soda,  for  each  100  kilogrammes  (220  Ibs.)  of  rice. 

Besides  the  species  of  grains  and  corn,  which  we 


138  MANUFACTURE   OF    STARCH,    ETC. 

have  described,  and  from  which  commercial  starch  is 
produced  to  advantage,  there  are  yet  quite  a  large 
number  of  plants  and  parts  of  plants  which  yield 
starch  in  various  quantities ;  but  none  of  them  suffi- 
cient or  of  a  corresponding  quality  to  guarantee  favor- 
able results  for  working  them  on  an  extensive  scale. 
It  is  therefore  deemed  sufficient  simply  to  name  these 
raw  materials  from  which  starch  can  be  obtained. 
They  are  as  follows:  Chestnuts,  barley,  rye,  oats, 
leguminous  plants,  buckwheat,  bran,  the  imperial  lily, 
arrow-root,  moss,  lichen,  sea-weed,  sago,  tapioca,  wood, 
acorns,  unripe  kernel  fruit,  and  several  other  plants. 

DISCERNMENT  AND  DETERMINATION  OF  THE  VARIOUS 
KINDS  OF  STARCH. 

When  we  consider  that  starch  is  so  extensively  dis- 
tributed, and  found  in  the  most  distinct  species  of 
plants  and  parts  thereof,  it  cannot  possess  in  all  cases 
identical  properties.  As  to  their  chemical  composition, 
the  different  kinds  of  starch  are  entirely  identical,  and 
if  a  difference  should  be  found  it  can  only  result  from 
foreign  substances,  which  adhere  to  the  starch.  But 
this  is  not  the  case  as  regards  the  physical  properties 
of  the  different  kinds  of  starch.  These  diverging  ap- 
pearances of  the' diverse  sorts  of  starch,  make  it  pos- 
sible to  classify  and  distinguish  them. 

For  the  purpose  of  distinguishing  the  various  kinds 
of  starch  as  well  as  to  test  them  with  regard  to  adul- 

o 

terations,  we  use  in  most  cases  the  microscope. 

The  following  interesting  table  will  be  useful  for  a 
classification  of  the  various  kinds  of  starch,  as  to  their 
forms  and  respective  sizes :— 


THE   TECHNOLOGY    OF    STARCH.  139 

A.  Grains  simple,  entirely  rounded  off  on  their 

surfaces. 

1.  Kernel   central;  layers 'concentric   and  pre- 
dominantly disk-shaped,  on  the  side   lentil- 
shaped  ;  kernel  rounded  or  radiating  slit. 

Wheat- Starch. 

Large  grains,  0.0352  (0.001386  inch)  to  0.0396 
millimetres  (0.001559  inch).  ' 

2.  Kernel  eccentric,  position  of  layers  plain  or 
meniscus-shaped,  as  with  the  cereal. 

Potato- Starch. 

Nucleus  mostly  on  the  narrower  end,  0.06  (0.00236 
inch)  to  0.10  millimetre  (0.0039  inch). 

B.  Grains  single  or  combined.     Single  granules, 

with  respect  to  the  separated  granules  either 
entirely  bounded  by  even  surfaces,  polygonic 
or  only  partly  so,  with  rounded  surfaces. 
Granules  throughout  polygonic. 
Hice- Starch. 

Many  with  large  kernel  cavity.     At  most  0.0066 

millimetres  (0.00026  inch). 
Maize-  Starch. 

Among  polygonic,  also  rounded  forms.  Mostly 
with  extensions  or  star-shaped  kernel  cavity. 
All  granules  free. 

The  Wheat- Starch  of  commerce  in  its  natural  condi- 
tion forms  mostly  very  white,  irregular-shaped,  poly- 
gonic, and  often  more  or  less  oblong  and  dry  pieces, 
hard  to  crush  or  bruise  between  the  fingers ;  when 
crushed  it  forms  a  crystal-white,  dull,  not  crummy  or 
loose  powder,  of  some  bluish  hue.  Viewed  through  a 
magnifying  glass  or  microscope,  the  wheat  starch 


140  MANUFACTURE    OF    STARCH,    ETC. 

grains  also  appear  glossy,  especially  under  a  glaring 
light,  but  not  in  such  a  high  degree  as  the  granules  of 
potato-starch.  Under  the  microscope  the  wheat-starch 
granules  show  a  more  or  less  spheroidal  rounded  form 
of  diverse  sizes.  The  central  part  of  the  concentric 
layers  of  the  granules  are  only  discernible  by  means  of 
a  500-fold  magnifying  power. 

To  distinguish  between  wheat-starch  and  the 
cheaper  potato-starch  is,  by  the  application  of  the  mi- 
croscope, easy.  The  granules  of  the  potato-starch  are 
larger  than  those  of  the  wheat-starch,  and  have  an 
irregular,  mostly  pear-shaped  form.  The  central  part, 
as  well  as  the  concentric  layers,  can  be  discerned  in 
the  potato-starch  even  by  the  use  of  a  magnifying 
glass  of  200-  to  300-fold  power. 

The  action  of  chemicals  on  the  wheat-starch  is  cha- 
racterized by  the  following  results :  If  1  gramme 
(15.43  grains)  of  this  starch  is  mixed  with  a  liquor  of 
6  cubic  centimetres  (1.62  flui drachms),  containing  25 
per  cent,  muriatic  acid  and  4  cubic  centimetres  (1.08 
fluidrachms)  water,  then,  by  shaking  the  same  for  ten 
minutes,  a  gelatinous  mixture  is  formed,  which  does 
not  possess  any  cabbage-like  odor,  like  the  potato 
starch.  One  part  of  wheat-starch  mixed  with  100  parts 
of  boiling  water,  forms  a  colorless,  somewhat  milky 
mucus,  with  a  bluish  hue. 

The  commercial  potato-starch  forms  powder-like 
crummy  fragments,  which  easily  fall  to  pieces,  and  can 
be  still  easier  crushed  between  the  fingers.  The  pow- 
der is  of  a  fine  grain,  by  the  light  of  the  sun  of  a  silky 
sheen,  but  of  less  whiteness  than  wheat-starch ;  its 
white  color  has  always  a  yellowish  tone.  Under  the 
microscope  the  potato-starch  granules  appear  larger 
than  those  of  wheat-starch,  more  oval  or  pear-shaped, 


THE    TECHNOLOGY    OF    STARCH.  141 

and  marked  with  shell-shaped  lines,  drawn  around  a 
centre  (nucleus),  usually  lying  on  the  narrower  end 
of  the  granule.  Potato-starch  has  a  greater  specific 
gravity  than  wheat-starch. 

The  action  of  chemicals  on  potato-starch  we  have 
already  investigated  while  explaining  that  of  wheat- 
starch,  and  but  little  in  this  respect  has  to  be  added. 
If  we  boil  1  part  of  potato-starch  in  100  parts  of  water, 
we  obtain  a  transparent  paste  with  grayish  tone  of 
color,  which,  however,  does  not  appear  milky  as  with 
wheat  paste.  If  1  gramme  (15.43  grains)  of  potato- 
starch  is  well  shaken  up  in  a  mixture  of  6  cubic  centi- 
metres (1.62  fluidrachms)  of  pure  muriatic  acid  of  25 
per  cent.,  and  4  cubic  centimetres  (1.08  fluidrachms)  of 
water,  then  a  jelly  is  formed,  which  has  a  peculiar  cab- 
bage-like odor,  or  like  that  of  the  fresh  unripe  hulls  of 
beans. 

Further  characteristics  of  wheat-  and  potato-starch 
are  the  following: — 

Wheat-starch  is  less  hygroscopic  than  potato-starch, 
since  the  former  contains  in  the  air-dried  state  but  12 
to  14  per  cent.,  the  latter,  however,  16  to  18  per  cent, 
of  water,  which  it  will  reabsorb  from  the  air,  even  if  it 
has  been  dried  very  carefully. 

The  specific  gravity  of  both  kinds  of  starch  is  exactly 
the  same,  to  wit,  1.53.  In  many  cases,  the  great  dif- 
ference in  the  diameter  of  the  single  starch-granules 
will  explain  the  origin  of  the  starch. 

The  stiffening  power  of  wheat-starch  is  greater  than 
that  of  potato-starch,  and  for  this  reason  it  is  preferred 
for  stiffening  linen  and  washed  clothes  as  well  as  for 
making  bookbinder's  paste.  In  the  paste  the  starch- 
granules  are  contained  in  the  form  of  gelatinous  lumps, 
which  in  the  potato-starch  are  much  larger  than  in 


142  MANUFACTURE   OF    STARCH,    ETC. 

wheat-starch  ;  this  causes  the  trouble  that  the  textiles, 
having  been  stiffened  with  potato-starch,  while  being 
smoothed  (or  ironed)  will  not  look  so  well,  as  the 
hot  iron  sometimes  shoves  off  these  miniature  lumps, 
or  balls  them  together,  which  never  occurs  when 
wheat-starch  is  used.  The  paste  of  wheat-starch  ex- 
posed to  the  air  remains  unaltered  for  a  long  time, 
while  potato-starch  paste,  after  but  a  few  days,  sepa- 
rates a  gelatinous  mass,  over  which  an  aqueous  and 
somewhat  sour  liquid  forms.  The  mass  mixed  again 
by  stirring  with  this  liquid  no  longer  possesses  the 
same  sticky  nature  which  the  fresh  paste  had.  Wheat- 
starch  is  therefore  preferable  to  potato-starch,  and 
would  have  long  since  supplanted  the  latter  entirely, 
if  the  former  wrere  as  white  and  pure  and  as  cheap  as 
potato-starch. 

As  has  already  been  stated,  the  paste  formation  of 
potato-starch  ensues  at  46°  to  62°  C.  (114.8°  to  1*43.6° 
F.),  while  wheat-starch  turns  into  paste  at  from  50°  to 
67.5°  C.  (122°  to  153.5°  F.).  In  its  dry  state,  potato- 
starch  forms  a  more  voluble  powder  than  wheat-starch. 
In  water  potato-starch  precipitates  much  faster  than 
wheat-starch,  which  latter  when  taken  out  of  the  water 
forms,  when  dried,  coherent  angular  pieces. 

Frequently  the  starch  of  the  grain  species,  particu- 
larly of  wheat,  is  considered  as  the  purest;  this  is 
nevertheless  erroneous,  since  potato-starch  can  be  pro- 
duced in  a  much  purer  condition,  because  no  removal 
of  the  gluten  brings  difficulties  as  is  the  case  with 
wheat-starch.  This  is  also  the  reason  why  commercial 
wheat-starch  always  appears  more  or  less  mixed  with 
gluten. 

Corn-starch  is  characterized  by  its  extraordinary 
power  of  stiffening,  exceeding  that  of  wheat-starch 


THE    TECHNOLOGY    OF    STARCH.  143 

in  a  high  degree.  Corn-starch  also  stiffens  textile 
fabrics  more  uniformly  than  wheat-starch. 

Chemists  of  great  celebrity  have  thoroughly  inves- 
tigated the  action  of  iodine  vapors  on  the  diverse  kinds 
of  starch,  the  results  of  which  are  herewith  given : — 

In  order  to  ascertain  the  reaction  of  iodine  with  ac- 
curacy, we  apply  a  square-shaped  glass  or  porcelain 
vessel  of  1  centimetre  (0.394:  inch)  high,  and  10  centi- 
metres (3.94  inches,  wide.  Into  this  vessel  we  pour  2 
grammes  (30.86  grains)  of  iodine,  with  20  grammes 
(308.60  grains)  of  fine  sand,  placing  over  it  an  air-tight 
fitting  glass  plate  on  which  a  thin  layer  of  the  starch, 
mixed  with  some  little  water,  is  put  by  means  of  a 
fine  brush.  The  coloring  of  the  starch  begins  within 
a  few  minutes  thereof,  whereupon  the  glass  plate  is 
taken  off,  and  after  the  starch  layers  have  become  dry 
the  shade  of  the  color  is  examined. 

By  the  influence  of  the  iodine  vapors  on  sundry 
kinds  of  flours  and  starches,  the  following  shades  of 
color  resulted : — 

Wheat-starch  .  .  .  violet. 

Potato-starch  .  .  .  turtle-gray. 

Dextrine showing  no  change  of  color. 

From  this  it  becomes  manifest  that  these  reactions 
ma}7  in  many  cases  be  of  useful  service,  as,  for  instance, 
in  the  case  of  starches  from  wheat  or  potatoes.  But 
some  mixtures  of  wheat-starch  with  potato-starch  can- 
not be  detected  in  this  manner,  since  if  the  admixture 
amounts  to  less  than  one-fifth  the  color  test  can  no 
longer  be  relied  on. 

Qobley's  method  of  testing  possesses,  however,  above 
all  others  the  advantage  of  being  more  easily  carried 
out.  It  serves  especially  for  the  purpose  of  examining 


144  MANUFACTURE    OF    STARCH,    ETC. 

the  sizing  paste  prepared  from  starch  which  is  used  in 
the  printing  of  calicoes. 

Mayet  has  made  experiments  with  regard  to  the 
action  of  caustic  potash  on  the  various  kinds  of  starch, 
and  has  rendered  an  account,  by  which  they  are  exam- 
ined, and  ascertained  with  tolerable  accuracy;  provided, 
however,  they  were  pure  and  unmixed  previous  to  the 
test.  According  to  this  method  5  parts  of  the  starch 
to  be  tested  are  mixed  with  5  parts  of  a  25  per  cent, 
solution  of  hydrate  of  potash,  previously  diluted  by 
60  parts  of  water.  By  this  method  the  following  re- 
sults are  obtained : — 

Potato- starch  furnishes  a  strong,  opalizing,  trans- 
parent substance  which  forms  a  stiff  jelly  within  half 
a  minute. 

Wheat-starch,  or  starch  of  the  grain  species  generally, 
does  not  become  stiff  even  after  the  lapse  of  thirty 
minutes,  rendering  a  milky  entirely  dull  mixture,  from 
which  no  starch  precipitates. 

QUALITY. — TEST  AS  TO  IMPURITIES  AND  ADULTERA- 
TIONS CONTAINED  IN  STARCH. 

The  amount  of  fixed  Water  in  Starch. — The  amount 
of  water  contained  in  starch  is  very  varying.  In  its 
green  state,  that  is,  when  freshly  prepared  and  deposited 
in  the  washing  vessels,  and  then  left  to  lie  for  from  24 
to  36  hours  on  a  water-absorbing  surface  (for  instance, 
gypsum  plate),  starch  will  contain  approximately  45.5 
per  cent,  of  water,  of  which  nothing  can  be  further  re- 
moved by  pressing.  When  regularly  dried  and  than 
exposed  to  a  damp  atmosphere  of  20°  C.  (68°  F.)  for  a 
period  of  several  days,  it  will  contain  an  average  of 


THE  TECHNOLOGY  OF  STARCH.         145 

35.75  per  cent,  of  water.  Stored  in  a  dry  magazine 
its  contents  of  moisture  amount  to  18  per  cent.  Totally 
dried  at  a  temperature  of  100°  C.  (212°  F.)  in  a  space 
void  of  air,  it  contains  finally  no  trace  of  water. 

The  fixed  water  of  a  good  commercial  starch  should 
not  exceed  18  per  cent.  By  drying  a  weighed  quan- 
tity of  such  starch  over  a  water  bath,  it  should  not  lose 
much  more  than  18  per  cent,  of  its  weight.  In  pur- 
chasing starch  it  is  of  great  importance  to  know  accu- 
rately its  contents  of  water,  since  finally  the  value  of 
the  starch  according  to  its  contents  of  water,  is  very 
varying. 

Several  methods  of  ascertaining  the  contents  of 
water  in  starch  have  been  proposed,  of  which  that  of 
Scheibler  deserves  the  first  consideration.  His  method 
is  based  on  the  principle  that  a  starch  containing  more 
than  11.4  per  cent,  of  water,  imparts  this  surplus  of 
moisture  to  alcohol  of  90°  Tralles  =  0.8339  specific 
gravity,  while  a  starch  of  less  moisture  absorbs  so  much 
water  from  this  alcohol  until  it  has  absorbed  enough 
water  to  form  11.4  per  cent.  The  increase  or  decrease 
of  the  watery  contents  of  the  alcohol  applied,  is  found 
in  the  change  of  its  specific  gravity,  and  this  becomes 
thus  a  measure  for  the  contents  of  water  of  the  starch 
to  be  tested. 

To  carry  out  such  a  test  1  weight  part  of  starch  is 
taken,  and  over  it  double  its  weight  of  alcohol  is 
poured,  weighing  in  a  normal  temperature  exactly 
90°  Tralles,  shaking  it  repeatedly  for  one  hour's  time, 
whereupon  it  is  filtered,  and  the  specific  gravity  of  the 
alcohol  flowing  off  accurately  ascertained.  To  sim- 
plify this  method  measuring  of  the  alcohol  may  be 

substituted  for  weighing.     For  each  100  cubic  centi- 
10 


146 


MANUFACTURE    OF    STARCH,    ETC. 


metres  (3.38  fluidozs.)  of  alcohol  of  90°  Tralles  =  83.39 

OO    OQ 

grammes  (2.92  ozs.  avoird.)  =  41.7  grammes 

A 

(1.46  ozs.  avoird.)  starch  should  be  taken. 

The  changes  thus  produced  in  the  specific  gravity 
of  the  alcohol  used  by  the  varying  amount  of  water 
in  the  starch,  are  fixed  by  a  series  of  experiments, 
and  the  following  table  has  been  prepared  in  accord- 
ance therewith.  It  will  only  be  necessary,  therefore, 
to  find  the  figure  next  that  found  as  the  specific 
weight  of  the  alcohol,  and  the  amount  of  water  of  the 
sample  of  starch  to  be  tested  is  ascertained  at  once. 

Table  for  ascertaining  the  contents  of  water  in  Starch. 


Water  con- 
teats  of  the 
starch. 
Weight  p.  ct. 

Specific 
gravity  of 
the  alcohol. 

Water  con- 
tents of  the 
starch. 
Weight  p.  ct. 

Specific 
gravity  of 
the  alcohol. 

Water  con- 
tents of  the 
starch. 
Weight  p.  ct. 

Specific 
gravity  of 
the  alcohol. 

0 

0.8226 

22 

0.8455 

44 

0.8643 

1 

0.8234 

23 

0.8465 

45 

0.8651 

2 

0.8243 

24 

0.8474 

46 

0.8657 

3 

0.8253 

25 

0.8484 

47 

0.8665 

4 

0.8262 

26 

0.8493 

48 

0.8673 

5 

0.8271 

27 

0.8502 

49 

0.8680 

6 

0.8281 

28 

0.8511 

50 

0.8688 

7 

0.8291 

29 

0.8520 

51 

0.8695 

8 

0.8300 

30 

0.8529 

52 

0.8703 

9 

0.8311 

31 

0.8538 

53 

0.8710 

10 

0.8323 

32 

0.8547 

54 

0.8716 

11 

0.8335 

33 

0.8555 

55 

0.8723 

12 

0.8346 

34 

0.8563 

56 

0.8731 

13 

0.8358 

35 

0.8571 

57 

0.8738 

14 

0.8370 

36 

0.8579 

58 

0.8745 

15 

0.8382 

37 

0.8587 

59 

0.8753 

16 

0.8394 

38 

08595 

60 

0.8760 

17 

0.8405 

39 

0.8603 

61 

0.8767 

18 

0.8416 

40 

0.8612 

62 

0.8775 

19 

0.8426 

41 

0.8620 

63 

0.8783 

20 

0.8436 

42 

0.8627 

64 

0.8791 

21 

0.8446 

43 

0.8635 

65 

0.8798 

For  practical  use  Scheibler  has  constructed  a  hydro- 
meter by  means  of  which  the  density  of  the  alcohol 
before  and  after  the  experiments  can  be  ascertained, 
and  from  its  scale  the  degree  of  water  contained  in  a 


THE   TECHNOLOGY    OF    STARCH.  147 

sample  of  starch  can  be  read  according  to  percentage. 
A  percentum  thermometer  combined  therewith  permits 
of  a  correction  caused  perhaps  by  a  deviation  from  the 
normal  temperature.  Of  late  an  instrument  has  been 
constructed  by  Block  which  is  designed  more  especially 
for  testing  the  water  contents  of  potato-starch.  The 
instrument  is  termed  a  "  Feculometer"  but  is  not  of  as 
much  value  as  the  first  described  contrivance,  inas- 
much as  it  does  not  accurately  determine  the  contents 
of  water  in  starch,  but  indicates  with  certainty  whether 
the  article  is  pure  or  spoiled. 

Testing  the  Starch  as  to  its  Impurities  with  reference 
to  Adulterations.  — The  various  kinds  of  starch  as  they 
appear  in  commerce  are  frequently  mixed  with  flour  of 
the  various  grain  species  and  other  foreign  substances 
of  organic  as  well  as  mineral  origin,  i.  e.,  are  adulter- 
ated. 

The  mixing  of  starch  obtained  from  different  kinds 
of  raw  material,  as  also  its  adulteration  with  flour, 
can  in  most  cases  be  proved  by  means  of  a  micro- 
scope. As  is  known,  the  various  kinds  of  starch  are 
distinguished  by  certain  characteristic  formations, 
while  the  flour  of  any  seed  species  also  contains,  be- 
sides the  starch-granules,  the  fragments  of  the  seed 
coats  and  of  the  hulls.  Besides  the  microscopic  me- 
thod, such  impurities  and  adulterations  of  the  starch 
may  also  be  proved  by  the  application  of  certain 
chemical  reagents. 

A  series  of  experiments  for  the  purpose  of  testing 
the  adulterations  of  starch  with  sundry  flours  and 
minerals  has  been  made  by  means  of  Gobley's  iodine 
reaction,  with  the  following  results  : — 

Potato-starch  mixed  with  wheat-flour  obtains — ex- 
posed to  the  vapors  of  iodine — a  somewhat  bluish  color, 


148  MANUFACTURE   OF    STARCH,    ETC. 

i 

which,  however,  only  appears  plainly  when  the  flour 
admixture  does  not  exceed  40  to  50  weight  per  cent. 

"Wheat-starch  adulterated  with  but  a  small  quantity 
of  flour  cannot  be  detected,  but  if  the  flour  admixture 
is  increased,  the  violet  coloring — caused  by  iodine  va- 
pOrs — decreases  in  clearness,  and  if  the  starch  layer  is 
allowed  to  dry,  black  specks  will  become  visible,  which 
in  pure  starch  are  never  noticed,  and  therefore  always 
indicate  the  presence  of  flour. 

Wheat-starch  mixed  with  one-third  potato-starch 
furnishes  in  comparison  with  the  reaction  of  the  pure 
wheat-starch  a  scarcely  traceable  difference ;  but  this 
deception  becomes  more  manifest  when  the  mixture  is 
stirred  in  hot  water.  Wheat-starch  mixed  with  roasted 
flour  in  the  proportion  of  one  part  to  one-third  shows 
in  the  coloring  a  very  considerable  difference  ;  the  color 
is  duller,  and  black  specks  are  visible.  Starch  mixed 
with  gypsum  can  be  detected  at  once,  because  the  gyp- 
sum does  not  color  at  all,  but  shows  white  specks, 
proving  the  presence  of  a  body  upon  which  iodine  has 
no  influence.  It  may,  however,  occur  that  by  this  test 
the  starch  strata  happen  to  lie  somewhat  thick,  and 
the  gypsum  may  be  entirely  covered  thereby,  so  that 
in  this  case  the  want  of  coloring  of  the  entire  mass 
cannot  be  noticed.  The  process  of  burning  such 
starch  to  ashes  is,  therefore,  always  preferable  to  the 
iodine  reaction. 

Starch  adulterated  with  sulphate  of  zinc  or  copper 
cannot  be  tested  by  the  iodine  process.  The  adultera- 
tions of  the  various  sorts  of  starch  can  in  many  cases 
also  be  tested  by  means  of  caustic  potash.  Wheat- 
starch  and  potato-starch  mixed  in  equal  weight  parts, 
treated  according  to  this  method,  furnished  a  semi- 


THE   TECHNOLOGY    OF    STARCH.  149 

transparent  gelatinous  substance  which  became  solid 
within  two  minutes. 

Four  weight  parts  of  wheat-starch  with  one  weight 
part  potato-starch  furnished  a  very  dense,  opaque,  and 
milky  mucilage. 

Four  and  a  half  parts  of  wheat-starch  with  one-half 
part  of  potato-starch  rendered  an  opaque,  milky  mucil- 
age, although  not  as  thick  as  the  former,  but  still  dis- 
tinguishable from  that  formed  with  pure  wheat-starch, 
by  not  running  off  in  drops  from  a  glass  tube  as  the 
latter  does. 

Very  frequently  starch  is  adulterated  with  various 
mineral  substances,  especially  with  ground  gypsum, 
with  glauber  salt  that  has  lost  its  crystallization 
water,  etc.,  less  frequently,  however,  with  powdered 
terra  alba,  white  marble,  chalk,  white  clay,  and  bolus 
and  sulphate  of  baryta. 

Whereas  the  ashy  contents  of  pure  starch,  whether 
manufactured  of  potatoes  or  grain,  etc.,  are  but  very 
insignificant,  the  determination  as  to  mineral  admix- 
tures can  be  simplified  by  the  incineration  of  a  certain 
weighed  quantity  in  a,  flat  vessel.  The  ashy  residue 
is  weighed  and  calculated  by  percentage.  A  residuum 
exceeding  but  1  per  cent,  of  the  weight  of  the  starch 
burned,  proves  the  admixture  of  foreign  substances. 

The  presence  of  gypsum  or  terra  alba  is  best  ascer- 
tained by  a  solution  of  chloride  of  barium.  To  this 
end  the  starch  is  mixed  with  water,  shaken,  filtered, 
the  liquor  treated  with  the  solution  of  chloride  of 
barium.  If  gypsum  or  terra  alba  is  present,  it  will 
form  a  white  precipitate,  which  is  insoluble  in  muri- 
atic acid.  The  presence  of  chalk  is  most  suitably 
tested  by  means  of  muriatic  acid.  When  over  the 
dry  starch  muriatic  acid  is  poured,  it  will  cause  effer- 


150  MANUFACTURE    OF    STARCH,    ETC. 

vescence,  and  the  solution  thus  gained  when  treated 
with  oxalate  of  potassium  will  furnish  a  white  precipi- 
tate. 

Clay  is  not  soluble  in  diluted  muriatic  acid,  or  is  but 
very  slightly  so,  and  baryta  not  at  all.  A  sample  of 
the  residue,  when  not  ascertained  as  gypsum,  heated 
on  burning  charcoal,  furnishes  when  moistened  with 
muriatic  acid  a  substance  smelling  like  sulphuretted 
hydrogen ;  while  the  muriatic  acid  solution  becomes 
dull  and  muddy  when  sulphuric  acid  is  added  thereto, 
and  thus  proves  the  presence  of  sulphate  of  baryta. 
Neither  of  these  two  reactions  results  if  clay  is  the 
means  of  adulteration. 

APPLICATION  OF  STARCH. 

Starch  is  applied  for  multifarious  purposes.  The 
best  qualities  serve  for  the  sizing  of  paper,  in  the  manu- 
facture of  this  article,  especially  for  preparing  fancy 
papers.  How  large  the  demand  for  starch  is  for  the 
manufacture  of  paper,  can,  for  example,  be  gleaned 
from  the  fact  that  to  the  paper  mass,  which  serves  for 
the  production  of  fine  paper,  usually  from  10  to  15  per 
cent,  green,  or  from  7  to  8  per  cent,  dry  starch  is 
added.  Thus  a  paper  mill,  producing  daily  from  1400 
to  1500  kilogrammes  (3080  to  3300  Ibs.)  of  prime 
quality  paper,  will  use  annually  from  50,000  to  75,000 
kilogrammes  (110,000  to  165,000  Ibs.)  and  more  of 
green  starch. 

For  the  manufacture  of  white  glucose-syrups,  for 
finishing  textiles,  for  making  white  dextrine,  as  well 
as  for  preparing  farinaceous  food  and  fine  pastry,  etc., 
the  finest,  perfectly  pure  starch  is  used.  On  the  other 
hand,  the  more  inferior  sorts  are  used  for  the  same 


THE   TECHNOLOGY   OF   STARCH.  151 

purposes  when  the  quality  of  the  product  is  not  of  such 
vital  importance,  as,  for  instance,  for  weaver's  dressing, 
as  means  for  thickening  the  strong  alkaline  solutions 
(mordants),  and  coloring  substances  for  cloth  printing, 
for  the  manufacturing  of  noodles  and  macaroni,  in  lieu 
of  tapioca,  sago,  etc.  Starch  forms,  furthermore,  that 
substance  from  which,  by  the  influence  of  certain 
agencies,  as  diastase,  etc.,  sugar,  and  from  it  alcohol  is 
produced.  It  forms,  therefore,  the  raw  material  for 
the  production  of  ardent  spirits  (brandies,  whiskeys), 
and  beer  and  ale,  etc. 

Another  important  application  which  starch  finds 
is  in  the  powdering  (dusting)  of  the  forms  in  metal 
foundries.  It  serves  in  this  respect  in  lieu  of  the  char- 
coal-dust formerly  used,  a  material  very  injurious  to 
the  health  of  the  workmen.  Starch  generally,  but 
more  particularly  that  made  of  potatoes,  is  an  excellent 
food  for  silkworms,  and  is  for  this  reason  thrown  on  the 
foliage  of  mulberry  trees.  The  use  of  starch  for  stiff- 
ening (starching)  linen  and  washed  clothes,  is  so  well 
known  that  we  deem  it  superfluous  to  dwell  upon 
it.  On  account  of  its  greater  cheapness  potato- 
starch  is  consumed  in  larger  quantities  than  wheat- 
starch.  Nevertheless,  great  quantities  of  the  latter  are 
steadily  produced,  because  it  has  for  certain  applica- 
tions advantages  which  the  potato-starch  lacks.  It 
stiffens  and  pastes  much  better,  swells  up  better,  and 
as  a  rule  is  whiter  than  potato-starch.  It  serves, 
therefore,  especially  for  finishing  white  textiles,  for 
bookbinder's  paste,  and  for  baking  fine  pastry.  For 
calico  printing  wheat-starch  is  also  best  suited  for 
some  colors,  while  potato-starch,  on  the  other  hand, 
is  more  applicable  for  finishing  those  textiles  whose 
colors  are  less  delicate  to  manipulate,  and  in  general 


152  MANUFACTURE   OP    STARCH,    ETC. 

for  those  uses  where  a  large  amount  of  adhesive  power 
or  delicacy  of  color  is  of  no  great  consequence. 

In  conclusion,  we  deem  it  of  some  interest  to  annex 
a  tabulary  synopsis  of  the  various  operations  necessary 
for  the  manufacturing  of  starch. 

Preparation  of  the  wheat. 

Steeping  of  the  wheat  until  it  becomes  soft. 

Pressing,  washing,  and  bruising. 

Washing  out  and  assorting  the  starch. 

Pressing  of  the  fine  starch. 

Gathering  and  edulcoration. 

Elutriation  and  assorting  of  the  commoner  starches. 

Drying  of  the  starch  in  brick-shape. 

Breaking  up. 

Finishing  the  process  of  drying  upon  frames. 

Preparing  corn  and  rice  for  starch  is  identical  with 
the  above  manipulations  of  wheat.  It  should  be  added, 
however,  that  the  finest  quality  of  starch  in  the  case 
of  wheat  is  finished  in  11|  days,  and  that  of  maize  in 
15  days,  and  hence  by  far  the  greater  part  of  the  entire 
fine  product  is  finished  much  earlier  than  is  the  case 
with  the  medium  and  ordinary  ones. 


PART  II. 

THE  M ARTIFACT  LTRE  OF  STARCH-SUGAR. 


SECTION  I. 

THE  CHEMISTRY  OF  STARCH-SUGAR. 

History,  Literature,  and  Terminology.  —  Professor 
Kirchhoff,  of  St.  Petersburg,  Russia,  made,  in  18 LI,  the 
important  discovery  that  starch  boiled  in  diluted  sul- 
phuric acid  is  transformed  into  sugar.*  Soon  after 
this  discovery  great  efforts  were  made  to  simplify  the 
process  of  Kirchhoff  for  making  sugar,  in  order  to  pro- 
duce this  article  as  cheaply  as  possible.  The  origin 
of  glucose  manufacturing  occurred  at  the  time  of 
Napoleon  I.,  when  the  English  were  blockading  the 
Continent,  and  it  caused,  therefore,  a  great  and  general 
sensation,  as  it  was  thought  at  that  time  that  grape- 
sugar  was  identical  with  cane-sugar,  and  hence  could 
in  every  respect  be  substituted  for  that  product. 

This  new  branch  of  industry  was,  therefore,  pursued 
with  rare  energy,  and  immense  quantities  of  such 
starch-sugar  were  manufactured;  and  this  industry 

*  Already  Foulcroy  and  other  chemists  knew  that  starch,  when 
treated  with  acids,  becomes  transformed  into  a  gummiferous  sub- 
stance. Aj;  a  later  period,  when  gum  was  a  very  expensive  article, 
Nasse,  who  co-operated  with  Kirchhoff,  found,  as  he  was  experiment- 
ing for  the  purpose  of  producing  gum  from  starch,  instead  of  gum, 
sugar,  without  this  being  his  intention. 


154  MANUFACTURE   OF   STARCH,    ETC. 

offered  at  that  time,  on  account  of  the  blockade,  mani- 
fold opportunities  for  establishing  extrordinarily  well- 
paying  enterprises. 

But  when  it  was  subsequently  proved  that  starch- 
sugar  was  by  no  means  identical  with  cane-sugar — 
being  less  soluble,  of  less  sweetness,  and  not  at  all 
suitable  to  serve  as  a  substitute  for  the  former — then 
this  product  was  for  a  number  of  years  without  demand, 
although  it  had  already  at  that  time  been  recommended 
for  the  manufacture  of  spirituous  liquors  and  for 
brewing  beer. 

Only  in  more  recent  times,  when  in  consequence  of 
the  greater  propagation  of  the  beet-sugar  manufacture, 
the  want  of  molasses  syrup  became  more  and  more 
felt  in  Europe  (since  the  East  India  syrup  could  not 
be  supplanted  by  the  sugar-beet  syrup),  the  manufac- 
ture of  glucose-syrup  as  well  as  starch-sugar  received 
more  attention.  The  importance  of  this  industry  was 
at  once  understood,  and  it  is  at  present  carried  on  in 
many  countries  with  great  success.  This  industry  is 
especially  flourishing  in  Austria  and  Germany,  where 
large  establishments  of  the  kind  exist  in  Brandenburg, 
Frankfort  on  the  Oder,  Kustrin,  and  in  Saxony,  while 
the  principal  factories  in  this  country  are  in  Buffalo, 
Chicago,  St.  Louis,  Peoria,  111.,  and  Danville,  111. 
The  raw  material  is  furnished  in  some  cases  from 
a  great  distance.  How  much  this  branch  oC  in- 
dustry has  been  developed  in  modern  times,  can  be 
gleaned  from  the  fact  that  Germany  alone  in  the  year 
1876  produced  in  her  47  glucose  and  starch-sugar 
syrup  factories,  from  41.75  million  kilogrammes  (91.85 
million  Ibs.)  of  green,  and  5  million  kilogrammes  (11 
million  Ibs.)  of  dry  starch,  14.8  million  kilogrammes 


THE    CHEMISTRY   OF    STARCH-SUGAR.  155 

(32.56  million  Ibs.)  of  syrup,  and  almost  11  million 
kilogrammes  (24.2  million  Ibs.)  of  solid  grape-sugar. 

The  literature  treating  on  this  interesting  subject 
is  abundant,  and  from  the  discovery  of  glucose  in 
1811  up  to  the  close  of  the  year  1880,  many  volumes 
have  been  published  in  the  various  languages  of  con- 
tinental Europe. 

The  terminology  grape-sugar,  starch-sugar,  potato- 
sugar,  uric-sugar,  dextrose,  glycose  or  glucose,  com- 
prises the  following  species  of  sugar  : — 

1.  The  diabetic  sugar. 

2.  The  solid  honey  sugar. 

3.  The  sugar  which  by  means  of  diastase  or  acids 
is  produced  from  starch  and  similar  substances. 

4.  The  products  of  the  action  many  acids  have  on 
cane-sugar,  and 

5.  The  sugar  contained  in  many  fruits.    All  of  these 
species  show  in  their  pure  state  and  freed  of  the  un- 
crystallizable  species  of  sugar  adhering  to  them,  the 
same  forms  of  crystallization  as  well  as  the  same  cir- 
cular-polarization. 

In  France  the  following  names  are  in  vogue : — 

a.  "  Glycose,"  according  to  Dumas,  is  the  generic 
name  for  grape-sugar  and  starch-sugar,  as  fully  iden- 
tical sugar  species. 

b.  "Starch-sugar"  or  "starch-syrup"  is  the  solid  or 
liquid  sugar  prepared  from  starch  by  the  aid  of  sul- 
phuric acid. 

c.  "Dextrine-sugar"  and  "dextrine-syrup"  are  the 
names  given  to  the  solid  or  liquid  product  obtained 
by  the  influence  of  diastase  on  starch. 

Wherein  found  and  in  what  percentage. — Sugar  is 
found  in  nature  in  three  different  forms,  as  so-called 


156  MANUFACTURE    OF    STARCH,    ETC. 

cane-sugar,  grape-sugar,  and  mucilaginous  sugar  (like- 
wise called  fruit-sugar,  levulose,  or  chylariose). 

Grape-sugar  is  largely  diffused  throughout  the  vege- 
table as  well  as  the  animal  kingdom,  and  is  found  in 
most  of  the  sweet-tasting  fruits,  and  in  many  parts  of 
plants  in  larger  or  smaller  quantities.  It  is  contained 
in  the  honey  of  the  bee,  and  is  separated  in  large  quan- 
tities in  the  urine  of  those  unfortunates  who  suffer  from 
that  disease  of  the  kidneys  known  as  diabetes  mellitus* 
In  the  various  kinds  of  fruits  grape-sugar  is  found  in 
the  following  quantities,  shown  in  the  mean  figure, 
viz.: — 

Apples 7.28-8.37  per  cent. 

Apricots 1.80 

Pears 7.45-10.80 

Blackberries.        .......     4.44 

Strawberries 5.73 

Whortleberries 5.78 

Raspberries 4.00 

Currants        .         .         .         .         .         .         .         .6.10 

Mulberries 8.19 

Mirabelles 3.58 

Peaches 1.57 

*  The  saccharine  compounds  belong  more  exclusively  to  one 
physiological  class  than  any  other  of  the  organic  constituents  of 
the  body.  Glucose  or  "  grape-sugar"  is  the  form  in  which  saccha- 
rine matter  is  normally  present  in  the  blood  and  chyle.  Cane-sugar 
when  introduced  into  the  system,  passing  into  the  circulatory  cur- 
rents, is  neither  assimilated  nor  removed  by  combustion,  but  finds 
its  way  out  of  the  system,  essentially  unchanged,  by  way  of  the 
kidneys;  on  the  other  hand,  glucose,  even  when  introduced  into  the 
system  in  much  larger  quantities,  is  entirely  appropriated  to  useful 
purposes,  not  a  trace  'of  it  being  discoverable  in  the  excrements. 
Indeed,  when  an  insufficient  quantity  of  the  required  sugar  is 
received  in  food,  the  liver  generates  liberal  supplies  from  starch  and 
other  sources.  The  liver  is  the  chief  sugar-creating  organ,  but  the 
protein  compounds,  in  certain  stages  of  decomposition  work  in  the 
same  direction. 


THE    CHEMISTRY    OF    STARCH-SUGAR.  157 


Plums 
Greengages  . 

.     »   . 

2.12  per  cent. 
3.12 

8  77 

Sweet  cherries 
Gooseberries 
Grapes  . 
Prunes  . 

10.79 
7.15 
14.93 
6.26 

In  the  sweet  sap  which  accumulates  in  the  honey 
cups  (nectarines)  of  plants,  fruit-sugar  is  found — 
mostly  along  with  cane-sugar — in  great  quantities. 
By  the  organism  of  the  bee,  however,  the  cane-sugar 
is  transformed  into  grape-sugar. 

Formation. — Grape-sugar  is  not  only  found  in  nature, 
but  can  also  be  produced  chemically.  Thus  it  is 
formed  as  a  result  of  the  action  of  diluted  acids,  dias- 
taste,  gluten,  saliva,  etc.,  on  starch,  and  for  this  reason 
starch  is  used  for  its  production,  in  the  first  place. 

Pure  starch  is  composed,  as  is  well  known,  and  ex- 
pressed by  the  formula — 

C12H2oOio,  or  C12H10O1o. 

If  the  starch  absorbs  two  molecules  of  water,  it  becomes 
transformed  into  glucose  (grape-  or  starch-sugar),  ac- 
cording to  the  formula 

Ci2H24Oi2,  or  Ci2H12O12. 

By  comparing  the  chemical  composition  of  the  starch, 
as  also  that  of  the  cane-sugar  and  grape-sugar  with 
each  other,  we  will  notice  at  once,  that  between  these 
three  combinations  an  intimate  affinity  exists,  and  that 
cane-sugar,  as  regards  its  composition,  is  betfween 
starch  and  grape-sugar,  i.  e.,  it  contains  one  molecule 
more  water  than  starch,  and  one  molecule  less  than  the 
starch-sugar,  according  to  the  following  formulae: — 
Ci2H20Oio,  or  Ci2H10Oio  =  Starch. 

H,  or  CJ2HuOii  =  Cane-sugar. 
^,  or  Ci2H12Ol2  =  Grape-sugar. 


158  MANUFACTURE    OF    STARCH,    ETC. 

In  the  same  manner  as  diluted  acid,  when  heated, 
acts  upon  the  starch  in  transforming  it  into  glucose  and 
dextrine,  so  also  other  organic  substances,  especially 
diastase,  gluten,  mouth  and  intestine  saliva,  blood 
serum,  kidney  substance,  gall,  etc.,  will  cause  a  like 
effect. 

This  same  process  of  transformation  we  observe  also 
in  the  germination  of  seeds,  as  in  the  tubers  and  bulbs 
of  many  plants ;  the  starch  is  transformed  into  sugar 
and  diastase,  which  therewith  furnish  to  the  developing 
young  plant  the  first  organic  nutriment.  A  similar 
transformation  takes  place  in  the  starch  of  the  potato 
when  it  freezes,  which  explains  the  sweet  taste  of  such 
potatoes. 

Saussure  has  drawn  attention  to  the  decomposition 
of  starch  in  consequence  of  putrefaction,  and  proves 
that  starch  paste  when  exposed  to  the  air  becomes 
sour,  in  consequence  of  a  formation  of  lactic  acid  ;  be- 
sides this  a  considerable  quantity  of  starch-sugar  is 
formed  during  the  process  of  putrefaction.  The  starch- 
sugar,  however,  is  not  formed  merely  from  starch  alone, 
but  also  from  fibrin  and  mucilaginous  substances,  fur- 
thermore from  cane-sugar  and  various  other  substances. 

As  early  as  the  year  1835  it  was  proved  that  all  acids 
— organic  as  well  as  inorganic — will,  in  a  more  or  less 
diluted  condition,  act  alike  on  cane-sugar,  by  trans- 
forming it  in  a  higher  temperature,  first  into  glucose 
or  grape-sugar,  next  into  ulmic  acid  (humicacid),  and 
that  by  admitting  air  it  turns  into  formic  acid.  Small 
quantities  of  any  diluted  acid  produce  decomposition 
in  the  same  degree  as  larger  quantities,  only  slower, 
according  to  the  degree  of  their  dilution. 

This  transformation  of  cane-sugar  into  grape-sugar 
is  explained  thus :  The  cane-sugar  is  converted  by  the 


THE   CHEMISTRY   OF    STARCH-SUGAR.  159 

action  of  the  diluted  organic  and  mineral  acids — in  the 
first  place  by  sulphuric  acid,  muriatic  acid,  etc. — into 
intervert  sugar,  which  latter,  according  to  Dubrunfaut, 
is  a  mixture  of  dextrose  (starch-sugar  or  glycose)  and 
levulose  (chylariose  or  mucilaginous  sugar). 

C12H22On  +  H2O  =  C6H1206  +  Cjal2O6. 

Cane-sugar.  Dextrose.  Levulose. 

Another  chemist  of  repute,  E.  M.  Raoult,  has  even 
found  that  cane-sugar,  under  the  influence  of  light, 
will  be  partly  converted  into  grape-sugar. 

Physical  Properties. — Grape-sugar  crystallizes  from 
its  aqueous  solution  in  hemispheric  warts,  or  shaped 
like  cauliflower,  and  absorbs  thereby  two  atoms  of 
water.  Its  chemical  composition  in  the  crystallized  con- 
dition is  therefore  expressed  thus:  CJ2H24Oi2+2H2O, 
or  C12H12O12+2HO.  When  heated  to  100°  C.  (212° 
F.),  it  melts  and  ejects  the  crystal  water;  the  anhy- 
drous grape-sugar  thus  obtained  gradually  absorbs 
again  from  the  moist  air  all  its  crystal  water. 

Glucose,  i.  e.,  grape-  or  starch-sugar,  when  polar- 
ized, turns  the  rays,  like  dextrine,  strongly  towards 
the  right,  while  fruit-sugar  turns  them  towards  the  left. 
The  taste  of  grape-sugar  is  not  as  sweet  as  that  of 
cane-sugar,  and  it  takes  two  and  a  half  times  as  much 
of  it  as  of  cane-sugar  to  sweeten  the  same  volume  of 
water. 

Process  of  Formation.  (Explanation  of  the  process 
occurring  ~by  the  transformation  of  starch  into  glucose 
and  dextrine.) — As  regards  the  process  which  ensues 
by  the  action  of  diluted  acids  and  diastase  on  starch, 
but  little  is  as  yet  known,  and  opinions  yet  greatly 
vary  with  regard  to  this  subject.  But  it  has  been 
proven  that  the  acids  during  this  process  of  trans- 


160  MANUFACTURE    OF    STARCH,    ETC. 

formation  of  the  starch  do  not  suffer  any  decomposi- 
tion, and  it  is  moreover  an  established  fact  that  the 
efficacy  of  the  diastase  is  limited,  but  in  what  manner 
glucose  and  dextrine  are  formed  from  starch  has  not 
yet  been  decided.  This  much  is  certain,  that  both  glu- 
cose and  dextrine  are  the  products  of  transformation 
produced  under  the  conditions  stated.  Thus,  for  many 
years  the  opinion  was  entertained  that  the  starch  gum 
— dextrine — forms  mainly  as  an  interim  product  during 
the  formation  of  glucose  from  starch,  i.  e.,  under  condi- 
tions which  are  favorable  to  its  formation,  and  is  further- 
more by  the  absorption  of  water  transformed  into  glu- 
cose. This  erroneous  opinion,  so  generally  diffused, 
was  first  refuted  by  Musculus  in  1861,  by  producing 
directly  and  simultaneously  dextrine  and  starch-sugar 
as  the  products  of  the  transformation  of  starch.  Be- 
sides this  Musculus  sought  to  prove  that  starch-sugar 
does  not  form  from  the  previously  obtained  dextrine 
by  absorbing  more  water,  but  for  the  most  part  in  a 
more  direct  way  from  the  starch.  Payeri,  another 
authority,  was,  however,  not  of  this  opinion,  and  fur- 
nished by  actual  experiments  the  proof  that  glucose- 
does  not  merely  form  from  starch,  but  is  also  obtained 
directly  from  dextrine  by  boiling  it  with  three  per  cent, 
of  sulphuric  acid,  and  also  by  the  action  of  diastase. 

The  difference  of  opinion  of  these  leading  scholars 
caused  a  highly  interesting  controversy  between  the 
two,  Payen  and  Musculus,  and  thus  became  the  subject 
of  a  heated  discussion  before  the  Academy  of  Science 
in  Paris. 

From  the  following  extracts  from  the  treatises  by 
Payen  and  Musculus,  a  clear  perception  may  be  ob- 
tained with  regard  to  the  processes  which  take  place 


THE    CHEMISTRY   OF    STARCH-SUGAR.  161 

during  the  transformation  of  starch  into  grape-sugar 
and  dextrine.  We  dwell  on  this  subject  more  minutely 
for  the  reason  that  it  will  tend  better  to  explain  the 
third  part  of  this  treatise — the  manufacture  of  dex- 
trine. 

The  Transformation  of  Starch  into  Grape-sugar  and 
Dextrine  according  to  T.  Musculus. — According  to  the 
view  accepted  by  men  of  science — says  Musculus — 
starch  is  first  transformed  into  dextrine  by  the  influ- 
ence of  the  diluted  acids,  before  it  is  changed  into 
grape-sugar,  since  dextrine  is  but  a  modification  of  the 
molecules  of  starch,  and  is  then  transformed  into  grape- 
sugar  by  absorbing  four  more  equivalents  of  water. 
By  the  investigations  which  I  undertook  in  regard  to 
this  subject  I  have,  however,  become  convinced  that 
the  process  is  a  different  one,  viz.,  that  the  forma- 
tion of  dextrine  and  glucose  is  rather  the  result  of  the 
decomposition  of  the  starch  than  of  a  mere  absorbing 
of  water.  In  order  to  determine  the  gradual  transforma- 
tion of  the  starch  into  grape-sugar,  I  used  a  titrated 
solution  of  tartarated  potash  of  oxide  of  copper,  and 
by  means  of  this  reagent  I  was  enabled  to  pursue  the 
process  with  accuracy.  My  opinion  with  regard  to 
this  matter  is  based  upon  the  following  facts : — 

a.  Diastase  has  no  effect  on  dextrine.  If,  for  in- 
stance, starch  is  brought  together  with  a  diastase 
solution  at  a  temperature  of  between  70°  and  75°  C. 
(158°  and  167°  *F.),  the  quantity  of  the  grape-sugar 
forming  increases  until  the  liquid  no  longer  turns  red 
or  blue,  when  testing  it  with  tincture  of  iodine.  At 
this  juncture  the  transformation  ceases,  although  much 
dextrine  is  yet  present,  a  fact  easily  proved  by  adding 
1  per  cent,  of  sulphuric  acid  and  then  boiling  it.  If 

now  an  equal  quantity  of  starch  is  added,  a  new  trans- 

11 


162  MANUFACTURE    OF    STARCH,    ETC. 

formation  ensues,  until  iodine  indicates  no  further 
presence  of  starch,  and  it  is  found  that  the  quantity 
of  the  sugar  formed  is  doubly  increased. 

5.  Grape-sugar  and  dextrine  appear  simultaneously, 
and  are  always  in  the  same  relative  proportion.  If  the 
process  is  interrupted  before  it  is  finished,  and  the  un- 
changed starch  is  separated  by  means  of  filtration, 
then  the  filtered  liquid,  which  now  no  longer  turns 
blue  by  applying  iodine,  contains  a  mixture  of  dex- 
trine and  starch-sugar  in  solution. 

In  order  to  ascertain  the  quantity  of  each  of  these 
substances,  I  determined  in  the  first  place  the  amount 
of  starch-sugar  by  means  of  the  tartarated  potash  of 
oxide  of  copper ;  thereupon  I  mixed  with  the  liquid 
1  per  cent,  of  the  sulphuric  acid,  placing  the  same  in 
a  strong  phial,  which,  hermetically  closed,  was  brought 
to  boiling  for  several  hours  in  a  strong  solution  of 
culinary  salt  at  a  temperature  of  108°  C.  (226.4°  F.), 
whereas  a  mere  boiling  at  common  pressure  does  not 
suffice  in  this  case.  The  reaction  may  be  considered 
under  all  circumstances  as  being  finished,  when  the 
quantity  of  sugar  no  longer  increases. 

I  have  always  found,  that  after  this  operation,  the 
quantity  of  the  sugar  was  three  times  as  large  as 
before.  The  mixture,  therefore,  consists  of  one  equiv- 
alent of  starch-sugar  and  two  equivalents  of  dextrine; 
this  relative  proportion  remains  the  same,  whether  the 
influence  of  the  diastase  has  just  commenced  or  has 
entirely  ceased. 

3C6H10O5  +  H20  =  2C0H1005  +  C,H12O6 


Starch.  Water.  Dextrine.  Starch  Sugar. 

c.  The  diluted  sulphuric  acid  operates  at  first  like 
the  diastase;  its  action,  however,  differs  in  so  far  that 


THE   CHEMISTRY    OF    STARCH-SUGAR.  163 

its  effect — although  weak — continues  after  transforma- 
tion of  the  starch.  If  starch  is  boiled  with  1  per  cent, 
of  sulphuric  acid,  which  has  previously  been  diluted, 
the  quantity  of  sugar  increases  rapidly,  until  the  liquid 
no  longer  becomes  blue  by  the  application  of  iodine. 
The  solution  then  contains  a  mixture  of  dextrine  and 
grape-sugar  in  the  proportion  of  2  :  1,  just  the  same 
as  if  the  diastase  had  been  applied.  By  continuing 
the  boiling,  the  reaction  becomes  very  feeble.  When 
I,  for  instance,  diluted  2  grammes  (30.86  grains)  of 
common  starch  in  200  cubic  centimetres  (6.75  fluidozs.) 
of  acidulated  water,  I  obtained  after  a  boiling  of  thirty 
minutes,  and  at  that  juncture  when  iodine  no  longer 
produced  a  coloring,  0.6  gramme  (9.26  grains)  sugar, 
while  thereafter  an  uninterrupted  boiling  for  a  period 
of  four  hours  was  required  to  attain  an  increase  of  30 
centigrammes  (4.62  grains)  of  sugar ;  notwithstanding 
the  fact,  that  the  liquid  still  contained  unchanged 
dextrine,  of  whose  presence  I  convinced  myself,  by 
exposing  the  liquid  in  a  closed  vessel  to  a  temperature 
of  100°  C.  (212°  F.).  If  starch-sugar  has  hitherto 
been  believed  to  be  a  product  resulting  from  the  dex- 
trine absorbing  more  water,  it  would  be  unexplainable 
why  its  formation  ensues  more  rapidly,  while  yet  un- 
changed starch  is  present  in  the  liquid  than  when 
merely  dextrine  is  left.  Certainly  if  the  above  opinion 
were  correct,  the  very  reverse  would,  as  is  obvious,  be 
th,e  case. 

d.  The  simultaneous  appearance  of  dextrine  and 
sugar  shows  itself  by  the  application  of  sulphuric  acid 
as  well  as  by  the  diastase,  and  the  proportion  in  both 
is  the  same. 

Since,  in  this  case,  the  starch  has  become  soluble  by 
boiling,  it  cannot  be  filtered  off,  but  it  must  needs  be 


164  MANUFACTURE    OF    STARCH,    ETC. 

precipitated  with  alcohol.  It  will  then  have  the  ap- 
pearance of  resin,  precipitated  by  water  from  an  alco- 
holic solution.  The  glucose  and  dextrine  remain  in 
the  solution,  and  can  be  determined  as  is  stated  in 
paragraph  b. 

From  my  observations,  the  following  practical  appli- 
cations result : — 

1.  In  the  manufacture  of  starch-sugar,  wherever  the 
influence  of  the  sulphuric  acid  is  considered  as  having 
ceased,  when  the  liquid  no  longer  is  colored  blue  by 
iodine,  and  alcohol  no  longer  produces  a  white  precipi- 
tate in  the  same,  a  large  quantity  of  dextrine  remains 
mixed  with  the  sugar,  and  since  the  same  does  not  fer- 
ment with  yeast,  it  will  cause  great  pecuniary  loss  to 
the  consumer.     The  manufacturers  of  glucose  must 
therefore,   in  order  to  obtain  a  good  product,   apply 
closed  vessels  at  an  increased  temperature. 

2.  The  great  resistance  which  the  dextrine  shows  to 
the  action  of  diluted  sulphuric  acid  furnishes  a  means 
for  titrating  a  mixture  of  cane-sugar  and  dextrine;  and 
it  suffices  to  boil  it  one  minute,  in  order  to  bring  all 
the   sugar  into  a  state  that  the  same  will  react  on  the 
tartaric  potash  of  oxide  of  copper.     During  this  period 
the  dextrine  suffer-s  no  change  whatever.     If  starch 
is  simultaneously  present,  it  is  to  be  transformed  by 
the  diastase,  which  does  not  influence  the  cane-sugar 
or  the  dextrine. 

3.  The  large  consumption  of  barley,  necessary  in 
breweries,  for  producing  a  beverage  which  does  not 
contain  too  much  alcohol,  finds  its  explanation  in  the 
mode  of  operating  of  the  diastase  ;  two-thirds  of  the 
starch  passes  over  into  the  beer  as  dextrine,  whereby 
the  beer   receives   a   somewhat  gummy  consistency, 
which  is  rather  in  its  favor. 


THE   CHEMISTRY    OF    STARCH-SUGAR.  165 

4.  In  the  distilling  of  brandies  and  whiskeys  of 
grain,  wherever  the  sugar  is  produced  by  germinated 
barley  (malt),  two-thirds  of  the  same  is  unavoidably 
lost. 

Thus  far  Musculus.  The  following  essay  shows 
Payen's  opinion  on  the  subject. 

Production  of  dextrine  and  starch-sugar  by  the  action 
of  sulphuric  acid  or  muriatic  acid  ;  by  means  of  diastase 
or  diastase  and  yeast  combined.  Extracting  the  wood- 
fibre  from  th  e  wood.  Manufa  cture  of  mucilag  inous  sugar 
by  means  of  malt  or  sidphuric  acid,  by  Anselm  Pay  en. — 
By  reading  the  report  which  Chevreul  submitted  to 
the  French  Academy  of  Science  respecting  the  history 
of  the  essays  treating  on  starch,  it  will  be  perceived 
that,  since  1716,  numerous  chemists  have  devoted 
themselves  to  the  investigation  of  this  matter.  But, 
notwithstanding  all  this,  this  highly  interesting  sub- 
ject is  even,  despite  all  the  researches  made  of  late, 
not  yet  thoroughly  exhausted.  Thus,  for  instance, 
neither  the  savants  nor  the  manufacturers,  who  of  late 
were  active  in  the  investigation  of  the  transformation 
of  starch  into  dextrine  and  glucose,  had  any  direct 
test  for  determining  the  relative  quantity  of  the  two 
substances  produced,  when  the  same  were  worked 
under  certain  conditions  of  time  and  modes  of  operation. 

Biot,  however,  was  the  first  who,  by  means  of  the 
optical  method  created  by  him,  observed  the  progress- 
ing trans-  and  sugar  formation.  It  has  generally 
been  accepted^  that  the  first  stage  of  the  process  fur- 
nishes the  maximum  of  dextrine  and  the  minimum 
of  sugar,  and  that  the  latter  increases  with  the  con- 
tinuance of  th*e  action.  But  no  endeavor  was  made 
to  fix  the  most  favorable  conditions  for  this  trans- 
formation, or  to  ascertain  the  limits  of  the  same  for 
the  various  agents.  When,  in  a  report  recently  made 


166  MANUFACTURE    OF    STARCH,    ETC. 

to  the  Academy,  it  was  stated  that  the  proportion 
of  2  :  1  was  the  right  one  which  existed  between  the 
constant  quantities  of  dextrine  and  sugar,  which  have 
formed  simultaneously  at  the  expense  of  the  starch 
by  the  intervention  of  water  and  diastase,  or  by  sul- 
phuric acid,  it  was  at  the  same  time  shown  that  the 
production  of  a  greater  quantity  of  sugar  by  the  dias- 
tase was  impossible,  and  by  means  of  sulphuric  acid  so 
difficult,  that  we  were  inclined  to  view  the  production 
of  the  two  substances  rather  in  the  light  of  being  a 
decomposition,  than  a  mere  increased  absorption  of 
water  on  the  part  of  the  starch  substance.  This  of 
course  tended  towards  the  proposal  of  making  a  con- 
siderable change  in  the  usual  method  of  manufacturing 
glucose  by  sulphuric  acid.  This  experience  led  more 
especially  to  the  application  of  closed  vessels,  and  to 
recommending  an  increase  of  the  temperature  or  pres- 
sure to  108°  C.  (226.4°  F.).  The  action  of  the  diastase 
on  starch  was  considered  as  being  incapable  of  trans- 
forming more  than  one-third  part  of  the  same  into 
sugar,  while  the  two  remaining  thirds  seemed  to 
withstand  all  the  further  formation  of  sugar  by  the 
same  means.  It  was,  for  instance,  thought  that  in  the 
distilling  of  brandies  from  grain  or  corn,  where  "  gene- 
rated" barley  (malt)  produces  the  fermentable  sugar, 
an  unavoidable  loss  of  two-thirds  of  the  alcoholic  pro- 
duct had  been  suffered. 

When  I  learned  of  these  interesting  observations — 
said  Pay  en — the  theoretical  conclusions  did  not  appear 
to  me  to  be  justified.  If  it  is  moreover  considered, 
that  those  parts  of  the  grain  containing  starch  possess  a 
very  varying  aggregate  in  the  single  grains,  and,  in  the 
ten  to  fifteen  single  concentric  layers  which  form  each 
grain,  show  alternately  a  maximum  and  a  minimum  of 


THE    CHEMISTRY    OF    STARCH-SUGAR.  167 

power  of  cohesion,  running  from  the  exterior  towards 
the  interior,  it  may  be  considered  as  probable  that  this 
different  condition  not  only  produces  many  noteworthy 
phenomena,  which  have  already  been  alluded  to  by  me 
some  time  ago,  but  it  also  tends  to  explain  the  rapid 
change  of  the  starch  into  two  different  products ;  the  one 
resulting  from  the  dissolution,  and  almost  immediate 
formation  of  sugar,  while  the  other  corresponds  with 
the  cessation  after  the  difficult  dissolution  of  the  denser 
parts.  It  seems  furthermore  probable,  that  this  resist- 
ance may  be  increased  by  the  presence  of  the  already 
formed  sugar,  and  that  it  may  be  possible  to  remove 
these  obstacles  either  partly  by  prolonging  the  in- 
fluence, or  still  more  completely  by  the  removal  of  the 
sugar  by  means  of  fermentation.  This  latter  opinion 
was  based  on  an  attentive  study  of  the  general  appear- 
ances displayed  during  the  chemical  process.  I  have 
made  these  observations  by  the  aid  and  co-operation  of 
the  renowned  chemist  Billevuin,  of  Paris.  The  results 
derived  therefrom,  and  which  are  based  on  the  ap- 
plication of  accurate  tests  of  the  various  products 
obtained  by  the  action  of  diastase  and  acids  on  starch 
and  dextrine,  as  also  those  which  relate  to  the  double 
action  of  the  diastase  and  yeast,  are  meantime  in  no- 
wise in  contradiction  with  the  "Manual"  which  I  pub- 
lished in  1843,  or  with  those  facts  which  I  have  pro- 
mulgated since.  Hence,  all  the  statements  with  regard 
to  the  various  forms,  sizes,  and  structures  of  the  starch 
in  the  different  plants,  and  regarding  their  various 
contents  of  water,  and  the  different  amount  of  cohe- 
sion in  the  same  starch-granules,  or  which  relate  to 
the  age  of  these  granules  as  well  as  to  the  manner  of 
their  solution,  and  their  penetrating  through  the  tex- 
ture during  the  life  process,  and  finally  to  the  occa- 


168  MANUFACTURE    OF    STARCH,    ETC. 

sional  return  of  the  same  to  their  original  state  and 
structure,  all  these  phenomena  remain  unaltered  and 
correct. 

On  the  other  hand,  all  these  later  experimental  in- 
vestigations extend  more  particularly  to  the  numerical 
determination  of  the  transformation  products  as  they 
form  under  various  conditions; — I  mean  both  during 
the  converting  of  the  starch  into  dextrine  and  sugar, 
as  well  as  during  the  conversion  of  the  dextrine  itself 
into  starch-sugar. 

It  had  been  my  intention  either  to  substantiate  the 
observations  communicated  by  Musculus,  or  to  set 
forth  new  facts,  which  may  serve  as  an  explanation  of 
many  processes  in  the  field  of  industry  and  agriculture. 

a.  The  first  of  the  mentioned  series  of  observations 
leads  to  the  finding  out  of  those  conditions  by  which 
we   will   be  enabled  to  obtain  in  a  direct  way  from 
51  to  83.6  per  cent,  of  starch-sugar  (Ci2H12O12)  from 
the   starch    substance,    by   means   of    a   3    per   cent, 
sulphuric    acid;    without     increasing     the    tempera- 
ture  of  the  liquid  above  the  boiling   point,  without 
varying  the  quantity  of  water  or  acid,  and  without 
causing  the  total  duration  of  action  to  last  longer  than 
from  three  and  one-half  to  five  hours.     Hence,  it  is- 
clear  that  the  starch  and  thereupon  the  greater  quan- 
tity of  the  dextrine  is'gradtially  transformed  into  sugar, 
and  consequently  it  is  not  necessary  to  work  closed 
vessels  in  order  to  transform  the  starch  into  so  much 
sugar  that  the  same  by  gradual  crystallization  con- 
geals into  a  solid  substance. 

b.  A  direct  experiment  has  proven  that  the  dextrine 
of  commerce,  under  similar  conditions,  will  furnish  a 
product  of  84  per  cent,  starch-sugar. 

c.  Another  series  of  experiments  proves  that  muriatic 


THE    CHEMISTRY    OF    STARCH-SUGAR.  169 

acid  acts  yet  somewhat  more  powerfully.  With  equal 
equivalents  and  according  to  the  method  of  operation 
it  furnishes  of  starch  a  product  which  contains  62^ 
to  85^  per  cent,  pure  starch-sugar. 

d.  If  muriatic  acid  is  permitted  to  act  under  simi- 
lar conditions,  but  for  a  longer  period  of  time  upon 
wood  fibre,  then  we  obtain  from  the  less  firm  fibrous 
substance  and  from  an  incrusting  substance  similar  to 
the  same,  in  the  first  place  dextrine,  and  then  fermen- 
table sugar,  while  the  denser  fibrous  substance  remains 
unchanged.      By  this  manner  two  different  products 
may  finally  be  obtained,  viz. :  alcohol  which  is  easily 
distilled  off,  and  fibrin  sufficiently  solid  to  be  applicable 
for  the  manufacture  of  paper.     From  beech-wood,  pine- 
wood,  poplar- wood,  and  the  straw  of  cereals,  from  10 
to  15  per  cent,  of  alcohol  can  be  thus  obtained,  and 
also  25  to  30  per  cent,  of  pure  dry  cellular  substance. 

e.  During  the  action  of  diastase  on  starch,  by  frac- 
tioning  it  off  four  times  within  the  space  of  two  and 
one-half  hours,  showed  steadily  increasing  amounts  of 
sugar,  thus :    17.9  per  cent.,  20.97  per  cent.,  25.89  per 
cent.,  and  finally  2G.03  per  cent,  of  the  dry  substance 
originally  used.     Thus  the  dextrine  formed  after  the 
liquefying  of  the  starch  changes  gradually  into  starch- 
sugar,  until  the  further  transformation  is  stopped  by 
the  forming  of  too  large  a  quantity  of  sugar. 

It  is  indeed  possible,  that  after  all  the  sugar  has  been 
removed  by  fermentation,  to  again  introduce  the  for- 
mation of  sugar  from  the  dextrine  by  further  applica- 
tion of  the  diastase,  and  realizing  the  same  amount  of 
sugar  as  previously.  Since  similar  products  have  been 
obtained  by  the  action  of  diastase  on  commercial  dex- 
trine, it  is  indeed  proved,  that  the  diastase  will  actually 
transform  the  dextrine  into  sugar. 


170  MANUFACTURE   OF   STARCH,   ETC. 

f.  A  further  series  of  experiments  has  proved  that 
brewer's  yeast  is  unable  to  cause  dextrine  to  ferment ; 
but  by  the  united  action  of  diastase  and  the  yeast, 
the  starch  is  in  the  first  place  transformed  into  dex- 
trine and  sugar,  and  the  latter  into  alcohol  and  car- 
bonic acid  gas.     Thus,  it  is  now  entirely  clear,  that  by 
following  the  directions   given   by  me   (Payen),  the 
almost  total  transformation  of  the  starch  into  alcohol 
will  be  accomplished. 

These  new  investigations  furnish  the  key  for  obtain- 
ing by  wise  management  a  better  result  in  distilling 
liquor  from  grain  or  brewing  beer  from  malt.  They  fur- 
nish the  conditions  which  must  be  observed,  if  the 
maximum  yield  shall  be  obtained,  and  they  also  explain 
the  remarkable  inconformities  which  sometimes  occur 
in  the  pursuit  of  these  operations  as  carried  on  in  large 
manufacturing  establishments. 

g.  In  another  series  of  experiments  the  starch  was 
mixed  with  warm  water  and  by  an  addition  of  more  water 
changed  into  thin  paste,  and  thereupon  subjected  to  the 
influence  of  the  diastase  at  certain  different  tempera- 
tures.     Thus  as   high  as  52.7   per  cent,  of  the  raw 
starch  was  transformed  into  starch-sugar.     If,  there- 
fore, none  of  my  (Payen's)  numerous  experiments  was 
able  to  produce  by  direct  sugar  formation  by  means  of 
diastase  a  higher  percentage  of  sugar  than  that  given 
by  the  above  figure,  how  could  the  figure  of  87.1  per 
cent.,  as  given  by  another  experimentator  (Musculus), 
ever  have  been  attained? 

h.  But  even  if  the  maximum  transformation  of  sugar 
is  reached,  the  syrup  obtained  from  the  dextrine  and 
sugar  will  not  be  directly  crystallizable. 

i.  In  the  same  manner  a  limited  result  was  only  ob- 
tained when  I  endeavored  to  effect  the  transformation 


THE    CHEMISTRY    OF    STARCH-SUGAR.  171 

of  starch  into  dextrine  without  the  formation  of  sugar 
by  85°  C.  (185°  F.).  Near  the  limit,  where  the  efficacy 
of  the  diastase  ceases,  the  two  products  of  this  special 
reaction  are  yet  forming  under  its  influence,  and  no 
exception  to  the  general  rule  does  therefore  take  place. 

If,  however,  the  diastase  operates  yet  upon  the  paste 
at  85°  C.  (1S5°  F.)  so  does  this  occur  only  because  it 
has  not  been  previously  brought  up  in  its  aqueous 
solution  to  this  temperature,  since  if  this  had  been 
done,  the  actual  limit  of  its  efficacy  would  sink  to  80° 
C.  (176°  F.). 

A§.  It  is  a  noteworthy  phenomenon  also  observed  by 
me  (Pay en),  that  the  diastase  still  manifests  its  effect 
at  temperatures  below  0°  C.  (32°  F.),  but  under  these 
circumstances  not  merely  dextrine  is  formed,  as  has 
been  alleged  by  Musculus,  but  I  found  also  upwards  to 
38.2  per  cent,  of  sugar  in  the  product.  Hence,  here 
too,  no  exception  to  the  general  rule  takes  place. 

I.  The  clear,  thick  syrups,  almost  without  color,  and 
without  a  tendency  to  crystallize,  as  they  are  now 
manufactured  and  offered  in  commerce  as  "  imponder- 
able syrups"  made  of  wheat,  maize,  or  malt,  are  pro- 
duced from  the  starch  of  potatoes  or  corn  by  means  of 
about  .007  of  their  weight  of  sulphuric  acid.  One  of 
the  finest  samples  contained  but  11.1  per  cent,  of  water, 
and  for  each  100  parts  of  dry  substance  used  47.73 
starch-sugar.  By  applying  these  syrups  in  lieu  of  the 
dextrine  syrups  made  from  starch  and  diastase,  the 
labors  of  the  manufacturer  have  doubtless  been  less- 
ened. Besides  this,  the  peculiar  malty  taste  has  been 
avoided;  but  in  doing  it  neither  as  pure  a  taste  of 
sugar  nor  as  much  mucilaginous  substance  is  obtained, 
which  recommends  the  syrups  of  dextrines  for  medici- 
nal purposes;  nor  were  those  advantages  attained, 

^     __^*^tJ  N^^. 

OF  TH« 


172  MANUFACTURE    OF    STARCH,    ETC. 

which  the  latter  syrups  made  of  malt  and  starch  afford 
to  the  beer  brewer. 

The  small  quantity  of  .007  sulphuric  acid  is  ample 
to  furnish  by  our  previously-mentioned  process  a  syrup 
whose  amount  of  sugar  will  be  69  per  cent,  of  the  ma- 
terial used,  and  it  may  be  done  in  an  open  vessel. 

m.  Although  but  little  acid  is  used  nevertheless  a 
certain  quantity,  however  small,  of  sulphuric  acid  and 
gypsum  will  always  remain  in  the  syrup  obtained, 
which  cannot  even  be  entirely  removed  by  filtration 
.through  a  thick  layer  of  coarse-grained  animal  charcoal. 

Meantime  the  contents  of  gypsum  are  much  less  in 
these  non-crystallizing  syrups  than  in  those  of  33°  B., 
or  in  the  crystalline  congealed  starch-sugar  of  40°  B. 
This  fact  tends  to  show  that  in  the  art  of  beer  brew- 
ing, these  products  should  be  substituted  by  syrups 
produced  by  means  of  diastase.  Such  a  change  would, 
beyond  doubt,  be  of  the  greatest  advantage  to  the 
wholesome  properties  of  this  beverage. 

Recent  Improvements  in  the  transformation  of  Starch 
into  Dextrine  and  Sugar. — In  a  treatise,  submitted  to 
the  French  Academy  of  Science  by  Musculus,  the  fol- 
lowing points  of  his  controversy  are  noteworthy: — 

"Pay en  believes  that  I  (Musculus)  have  been  mis- 
led by  the  peculiar  structure  of  the  starch  granules, 
inasmuch  as  I  could  accidentally  have  found  a  mixture 
of  sugar  and  dextrine,  in  consequence  of  the  greater 
or  smaller  aggregation  of  the  individual  layers  of  the 
granules.  But  it  is  the  fundamental  experiment,  com- 
municated by  me  in  my  previous  treatise,  which  has 
led  me  to  an  entirely  different  opinion  from  that  so 
generally  accepted,  leaving  entirely  out  of  considera- 
tion the  structure  of  the  starch  granules. 


THE    CHEMISTRY    OF    STARCH-SUGAR.  173 

The  test  is  as  follows  :  — 

When  starch  is  treated  in  a  solution  of  diastase,  and 
the  gradual  forming  of  sugar  is  determined  from  time 
to  time,  it  will  be  found  that  the  quantity  of  the  sugar, 
until  the  transformation  of  the  starch  is  complete, 
steadily  increases — which  may  be  easily  perceived  by 
testing  with  a  solution  of  iodine.  After  this  point  is 
reached  no  more  sugar  will  be  formed  however  long  the 
heating  may  be  continued,  although  some  unchanged 
dextrine  remains  in  solution,  as  Pay  en  hi  mself  has  found. 
But  whenever  a  new  quantity  of  starch  is  added  the 
formation  of  sugar  again  begins  to  cease  as  soon  as 
the  starch  is  converted,  and  so  on  until  the  effici- 
ency of  the  diastase  is  exhausted,  i.  e.,  when  according 
to  Persoz  and  Payen  1  part  of  the  diastase  has  dis- 
solved 2000  parts  of  starch.  How  can  this  pheno- 
menon be  explained  if  we  suppose  that  starch  in  the 
first  place  is  transformed  into  dextrine  and  then  into 
sugar?  In  this  case  we  must  needs  suppose  that  the 
diastase  would  act  with  a  stronger  effect  upon  one 
part  of  the  dextrine  than  upon  the  other,  which  of 
course  is  impossible. 

If  the  starch  is  treated  with  diluted  sulphuric  acid 
instead  of  diastase,  the  same  process  of  transformation 
takes  place,  but  the  formation  of  sugar  still  progresses 
even  then— although  very  slowly — when  the  starch  has 
become  entirely  decomposed.  This  also  has  been 
acknowledged  by  Payen,  since  he  had  to  keep  up  the 
heating  for  five  hours  in  order  to  obtain  the  maximum 
yield  of  sugar.  Since  this  operation  progresses  faster 
by  an  increased  than  by  a  normal  pressure,  I  suggested 
to  bring  about  the  transformation  of  starch  into  sugar 
in  closed  vessels ;  hoping  by  this  method  to  work  less 
expensively  and  to  attain  a  less  colored  product;  it 


174  MANUFACTURE    OF    STARCH,    ETC. 

being  a  well-known  fact,  that  a  solution  of  sugar  by 
continued  boiling  becomes  brown.  If  to  the  mixture, 
already  boiled  by  an  increased  pressure,  fresh  starch 
be  added,  the  formation  of  the  sugar  is  greatly  accel- 
erated, and  the  liquor  thus  obtained — when  the  starch 
has  been  worked  in  the  form  of  thin  paste — will  no 
longer  react  blue  with  tincture  of  iodine  after  boiling 
about  thirty  minutes. 

When,  as  already  stated,  the  constant  quantities  of 
dextrine  and  sugar,  which  are  formed  by  this  process, 
stand  in  the  proportion  of  2  :  1,  I  desired  to  designate 
only  those  quantities  which  originated  from  the  direct 
decomposition  of  the  starch.  It  is,  therefore,  not 
remarkable  that  Pay  en  does  not  agree  with  me, 
although  in  order  to  find  this  proportion,  I  interrupted 
the  operation  at  the  moment  when  the  tincture  of 
iodine  indicated  the  disappearance  of  the  starch,  while 
Pay  en  continued  the  heating  until  the  entire  cessation 
of  the  formation  of  sugar. 

Meanwhile  the  conformity  is  again  established  when 
the  experiment  of  Pay  en  ad  e  is  compared  with  that 
of  ad  a.  By  the  experiment  ad  e,  Payen  obtained  by 
the  action  of  the  diastase  Z6.03  per  cent,  of  sugar,  but 
by  the  experiment  ad  a,  whereby  he  exhausted  the 
effect  of  the  sulphuric  acid  (which  had  been  added  in 
the  proportion  of  3  per  cent.),  he  reached  83.6  per  cent, 
sugar,  which  approaches  the  ratio  as  specified  by  me. 
It  becomes  manifest  that  by  Pay  en's  experiment  ad  e, 
the  diastase  merely  transformed  the  starch  into  sugar, 
while  by  the  experiment  ad  a,  by  means  of  the  con- 
tinuous action  of  the  sulphuric  acid,  sugar  was  formed 
directly  from  starch  as  well  as  from  dextrine. 

Payen  states,  that  another  experiment  with  diastase 
and  starch  resulted  in  a  gain  of  starch-sugar  of  up- 


THE    CHEMISTRY    OF    STARCH-SUGAR.  175 

wards  of  50  per  cent.,  when  he  caused  the  diastase  to 
act  upon  paste;  an  amount  which  I  (Musculus)  could 
never  reach,  even  when  I  continued  the  heating  for 
twenty-four  hours  more,  after  the  starch  had  dis- 
appeared. This  result  would  prove  that  the  starch- 
sugar  would  only  incompletely  balance  the  effect  of 
the  diastase  on  the  dextrine,  and  thus  the  mode  of 
operation  of  the  diastase  and  that  of  the  diluted  sul- 
phuric acid  would  be  shown  as  more  nearly  similar. 
But  if  starch-sugar  prevents  the  further  formation  of 
sugar  from  dextrine  more  or  less,  it  does  not  prevent 
its  formation  from  starch  direct,  whence  it  follows, 
that  as  long  as  starch  is  contained  in  the  liquid,  the 
dextrine  will  not  be  acted  upon. 

And  finally  Payen  found  that  the  action  of  the  dias- 
tase takes  place  somewhere  near — 10°  C.  (14°  F.),  and 
that  at  this  low  temperature  as  well  as  at  some  higher, 
a  mixture  of  sugar  and  dextrine  is  always  created. 
Never  yet  has  dextrine  been  obtained  without  some 
sugar.  I  believe  that  this  result  may  be  considered 
as  a  confirmation  of  my  statements. 

On  the  Effect  of  Diastase  on  Starch  under  various 
conditions. — A.  Payen,  in  reply  to  the  above  treatise 
of  Musculus  says :  Musculus'  pamphlet  contains  the 
following  three  concluding  results,  viz: — 

1.  The  diastase  does  not  act  on  the  dextrine. 

2.  The  diastase  always  produces  by  its  action  starch- 
sugar  and  dextrine  in  the  same  proportion,  to  wit,  one 
part  sugar  and  two  parts  dextrine. 

3.  In  the  distillation  of  spirits  from  grain,  whereby 
the  formation  of  sugar  is  effected  by  means  of  germi- 
nating barley,  an  unavoidable  loss  of  two-thirds  of  the 
latter  takes  place. 

These  three  conclusions  are  not  admissible.     They 


176  MANUFACTURE   OF    STARCH,    ETC. 

are  in  contradiction  to  the  established  results  of  seve- 
ral older  investigators  on  starch,  but  more  especially 
to  the  results  of  my  own  experimental  tests. 

I  have  resumed  these  investigations,  and  have  been 
successful  in  ascertaining  the  causes  of  the  different 
results,  and  am  able  to  prove  with  accuracy  : — 

1.  That  the  diastase  operates  on  the  dextrine,  and 
can  partially  pass  the  same  over  into  sugar. 

2.  That  the  diastase,  while  operating  on  the  starch, 
can  produce  dextrine  and  sugar  in  different  propor- 
tions, according  to  circumstances,  and  within  the  lim- 
its of  17  to  50  per  cent.,  and  even  more  of  sugar  can 
be  realized  from  the  entire  product. 

3.  That  in  the  manufacture  of  high  wines  from  grain 
the  entire  quantity  of  starch,  excepting  but  a  small 
percentage,  can  be  gradually  changed  into  sugar  and 
alcohol. 

After  having  established  the  latjter  point  experi- 
mentally, I  have  for  several  years  followed  up  these 
results,  and  proved  them  on  a  larger  scale  by  some 
of  the  ablest  distillers  of  grain  spirits.  With  regard 
to  the  first  point,  I  have  proved  the  action  of  the 
diastase  on  dextrine,  by  using  dextrine  obtained  by 
two  different  methods  of  manufacture. 

The  one  kind  of  dextrine  was  pulverized,  and  was 
such  as  is  made  in  the  manufactories  by  the  action  of 
a  very  small  quantity  (0.005  gramme,  0.077  grain)  of 
muriatic  acid  upon  starch  at  a  temperature  of  120°  C. 
(248°  F.).  The  solution  of  this  dextrine  was  neutralized 
with  carbonate  of  ammonia,  and  thereupon  treated  with 
a  solution  of  diastase  for  a  period  of  four  and  a  half 
hours  at  70°  C.  (158°  F.),  after  which  the  250  cubic 
centimetres  (8.44  fluidounces)  liquid,  being  the  pro- 


THE    CHEMISTRY    OF    STARCH-SUGAR.  177 

duct  of  20  grammes  (308.6  grains)  dextrine,  contained 
5.065  grammes  (78.16  grains)  of  sugar,  viz.: — 

For  100  grammes  (3.5  ozs.  avoir.)  dextrine 

sugar 25.235 

Deduct  therefrom  the  original  amount  .         .        5.23 

The  product  of  the  sugar  formation  by  means 

of  the  diastase  amounted  to         ...      20.005 

The  other  dextrine  was  obtained  by  removing  all 
sugar  from  a  liquor  which  had  been  prepared  by  the 
action  of  the  diastase  on  starch.  The  sugar  was  in 
this  case  removed  by  fermentation.  The  solution  of 
this  dextrine  was  evaporated  until  dry,  the  residuum 
weighed  and  again  dissolved  in  water,  then  exposed 
to  the  action  of  the  diastase  at  a  temperature  of  75° 
C.  (167°  F.).  From  an  amount  of  4.3  grammes  (66.3 
grains)  dextrine  used,  were  obtained  1.154  grammes 
(17.8  grains)  of  sugar,  or  26.8  per  cent,  sugar  for  each 
100  of  dextrine.  By  this  it  has  been  proven,  that  the 
dextrine  by  the  diastase  is  partly  transformed  into 
sugar.  Furthermore,  from  this  fact  the  conclusion 
can  be  drawn,  that,  the  further  formation  of  sugar  is 
prevented  by  the  presence  of  sugar,  since  after  the 
removal  of  the  latter  the  diastase  has  again  mani- 
fested its  former  power  to  form  sugar.  And  beside  all 
this  we  may  conclude,  that,  during  the  alcoholic  fer- 
mentation of  this  mixture  of  diastase  with  various 
quantities  of  starch,  dextrine,  and  sugar,  the  real  obsta- 
cle disappears  in  the  same  ratio  as  the  sugar  changes 
into  alcohol  and  other  products,  and  the  diastase  in 
consequence  thereof  regains  its  efficacy. 

In  the  first  place,  two  experiments  proved,  that  the 

alcoholic  fermentation  alone  (after  the  action  of  the 
12 


178'  MANUFACTURE   OF    STARCH,    ETC. 

diastase  was  stopped  by  boiling)  is  unable  to  change 
dextrine  into  sugar.  A  third  experiment  was  made, 
with  the  intention  of  effecting  the  fermentation  of  that 
substance  which  had  been  converted  into  sugar  by  the 
diastase,  and  at  the  same  time  not  to  weaken  the 
strength  of  the  diastase.  100  grammes  (3.5  ozs.  avoir.) 
of  starch  were  boiled  into  paste  in  1  litre  (2.1  pints) 
of  water,  the  temperature  lowered  to  25°  C.  (77°  F.), 
and  thereupon  by  the  application  of  malt  a  liquor  was 
produced  within  the  period  of  two  hours,  which,  after 
filtering,  contained  6.72  per  cent,  of  dry  substance, 
wherein  were  contained  41  per  cent,  of  sugar  and  59 
per  cent,  of  dextrine.  The  rest  of  the  liquid  which 
was  not  filtered  we  allowed  to  ferment  with  yeast,  for 
eleven  days,  which  caused  one  part  of  the  paste  to 
become  liquid.  100  grammes  (3.5  ozs.  avoir.)  of  the 
filtered  solution  contained  2.5644  grammes  (39.57 
grains)  of  alcohol ;  while  the  2.76  grammes  (42.58 
grains)  of  sugar,  which  had  been  present  before  the 
fermentation,  corresponded  only  with  1.41  grammes 
(21.76  grains)  of  alcohol.  The  surplus  found,  i.  e., 
1.56  grammes  (24.07  grains)  of  alcohol,  corresponds 
at  least  to  2.261  grammes  (34.89  grains)  sugar,  which 
were  produced  by  the  action  of  the  diastase  on  the  dex- 
trine, in  the  same  ratio  as  the  obstacle  to  this  trans- 
formation disappeared.  The  formation  of  sugar,  there- 
fore, had,  in  consequence  of  its  continuation  during 
the  alcoholic  fermentation,  almost  doubled  its  original 
amount'  by  its  action  on  the  dextrine.  Even  6  per 
cent,  more  of  the  same  might  be  found,  if  the  subsidiary 
products  were  brought  into  account.  It  is  therefore 
obvious  that  distillers,  instead  of  unavoidably  losing 
at  least  two-thirds  of  the  substance  which  passes  into 
alcohol  and  sugar,  will,  by  careful  manipulation,  rather 


THE   CHEMISTRY   OF    STARCH-SUGAR.  179 

reach  within  a  small  percentage  of  the  production 
which  is  theoretically  possible. 

Thus  it  remained  yet  merely  to  investigate  whether 
diastase  by  its  action  on  starch  does  always  produce 
sugar  and  dextrine  in  the  proportion  of  1  :  2.  We  will 
see  that  this  proportion,  according  to  circumstances, 
may  greatly  vary. 

A  series  of  experiments,  in  which  a  mixture  of  100 
grammes  (3.5  ozs.  avoir.)  of  starch  were  heated  to  75° 
C.  (Ib7°  F.)  with  15  grammes  (231.45  grains)  pul- 
verized malt  and  1000  grammes  (35  ozs.  avoir.)  of 
water  in  a  water-bath,  furnished  the  following  propor- 
tions : — 

After             After  After 

20  minutes.  28  minutes.  78  minutes. 

Sugar    .        .        .        .17.9            20.97  25.83 

Dextrine        .        ."      .     82.1             79.03  74.17 

After  the  process  had  been  so  modified  that  the 
action  of  the  diastase  on  the  previously  watery  and 
partly  dissolved  starch  was  quickened,  the  transforma- 
tion of  the  latter  furnished  a  larger  proportion  of  sugar 
and  a  smaller  proportion  of  dextrine. 

Into  a  paste  of  20  grammes  (308.6  grains)  starch, 
and  200  grammes  (7  ozs.  avoir.)  of  water,  which  was 
brought  to  75°  C.  (167°  F.)  and  kept  at  that  tempera- 
ture, 20  grammes  (303.60  grains)  of  malt  were  quickly 
stirred,  and  in  the  dry  substance  of  the  evaporated 
liquid  were  found — 

After  2  hours.  After  22  hours 

at  500  c.  (122QF.) 

Dextrine     ....     58.94  57.37 

Sugar 41.06  42.63 

In  order  to  be  brief  I  will  abstain  from  a  more  elabo- 
rate explanation  of  three  experiments  which  furnished 
43.17,  43.16,  and  43.36  per  cent,  starch-sugar,  but  I 


180  MANUFACTURE   OF    STARCH,    ETC. 

will  state  the  conditions  by  which  I  succeeded  in  car- 
rying on  the  formation  of  sugar  still  further : — 

50  grammes  (1.75  ozs.  avoir.)  of  starch  were  mixed 
with  400  cubic  centimetres  (13.5  fluidounces)  of  water 
having  a  temperature  of  100°  C.  (212°  F.),  while  con- 
stantly stirring,  and  thus  a  temperature  of  about  92°  C. 
(197.6°  F.)  was  obtained ;  thereupon  the  temperature 
was  allowed  to  run  down  to  25°  C.  (77°  F.),  and  7.5 
grammes  (115.72  grains)  of  malt  were  stirred  in,  and 
the  temperature  kept  at  25°  C.  (77°  F.),  while  an  oc- 
casional stirring  of  the  mixture  took  place. 

The  dry  substance  of  the  solution  contained — 

After  After 

4  hours.  6  hours. 

Dextrine         .         .        .         .         .     55.17  52.14 

Starch-sugar.         .         .         .         .44.83  47.86 

100.00  100.00 

Another  experiment,  in  which  the  temperature  was 
maintained  during  two  hours  and  forty-five  minutes  at 
40°  C.  (104°  F.),  furnished  100  parts  of  dry  substance, 
of  which  49.33  per  cent,  were  sugar  and  50.67  per  cent, 
dextrine. 

;  Notwithstanding  this,  the  maximum  of  sugar  to  be 
obtained  by  the  action  of  the  diastase  had  not  been 
reached.  Two  further  experiments,  the  one  at  a  con- 
stant temperature  of  50°  C.  (122°  F.),  the  other  at  40° 
C.  (104°  F.),  and  each  experiment  being  divided  by  two 
periods,  proved  that  the  formation  of  sugar  still  con- 
tinues for  a  short  time  after  the  complete  liquefying, 
and  that  the  maximum  of  sugar  may  amount  to  more 
than  50  per  cent,  of  the  entire  product. 


THE   CHEMISTRY   OF   STARCH-SUGAR.  181 

Istexp.  at500G.(1220F.)    2d  exp.  at  4(P  C.  (104°  F. ) 


' 

After 

After 

After 

After 

4  hours. 

6  hours. 

2£  hours. 

4£  hours. 

Dextrine 

.     53.4 

50.099 

52.876 

48.05 

Starch-sugar 

46.6 

49.901 

47.124 

51.95 

100.0       100.000  100.000       100.00 

The  maximum  of  sugar  which  may  be  directly  ob- 
tained may  therefore  greatly  exceed  the  limits  of  33 
per  cent.,  a  fact  not  deemed  possible  by  Musculus. 

Final  results: — 

1.  By  the  action  of  diastase  upon  dextrine,  sugar 

is  formed.. 

2.  The  action  thereof  suffers  an  interruption  by 

the  presence  of  starch-sugar,  but  is  re-estab- 
lished when  the  sugar  is  removed. 

3.  When  the  starch-sugar  is  transformed  by  fer- 

mentation into  alcohol,  and  thereby  the  for- 
mation of  sugar  from  dextrine  is  no  longer 
impeded,  the  action  of  the  diastase  returns, 
and  thus,  instead  of  losing  66  per  cent,  (ac- 
cording to  Musculus)  of  the  starch-containing 
substances  in  the  manufacture  of  spirituous 
liquors,  the  entire  quantity  of  the  starch  is 
gradually  transformed,  excepting  but  a  small 
percentage,  into  sugar,  alcohol,  and  subordi- 
nate products. 

4.  If  the  diastase  is  caused  to  act  upon  the  starch 

under  favorably  arranged  circumstances,  not 
only  more  than  33  per  cent,  of  sugar,  but 
even  more  than  50  per  cent,  of  the  same,  can 
be  obtained. 

Annotations  to  Pay  erf  s  Essay,  ~by  Q.  0.  Htibicli. — 
The  renowned  technician  Habich  submits  the  follow- 


182  MANUFACTURE    OF    STARCH,    ETC. 

ing  interesting  notes   respecting   Payen's   assertion, 
ad  4:— 

It  is  an  indisputable  fact  that  the  dextrine  contained 
in  our  concentrated  extracts  of  malt  does  ferment,  or 
plainer  told,  does  get  transformed  into  grape-sugar 
dining  the  second  fermentation. 

,  Notwithstanding  this,  Payen  has  endeavored  to 
prove  by  his  experiments  that  this  fact  is  a  myth.  He 
has  tried  to  show  by  two  experiments  that  the  alcoholic 
fermentation  alone  (after  removing  the  action  of  the 
diastase  by  boiling)  will  not  change  dextrine  into  sugar. 
The  sense  of  this  sentence,  according  to  how  much 
importance  is  attached  to  these  unknown  experiments, 
may  be  expressed  by  the  two  following  sentences: — 

1.  After  the  quantity  of  sugar,  which  was  known  as 
a  maximum  obtained  by  the  mash-process,  had  been 
decomposed,   no   further   formation    of    alcohol    took 
place. 

2.  The  amount  of  dextrine  fixed  prior  to  the  fer- 
mentation was   found,  after   the   fermentation,  to   be 
undiminished. 

We  will  furnish  the  proof,  that  Payen  could  not 
possibly  have  obtained  the  above  results.  In  order  to 
make  the  position  of  Payen  as  advantageous  as  possi- 
ble, we  will  investigate  the  experiment  relating  to  the 
largest  yield  of  sugar  (to  wit,  second  experiment  at 
40°  C.)  (104°  F.),  by  which  48  per  cent,  dextrine  and 
52  per  cent,  sugar  were  obtained.  The  extract  of  malt 
and  hops  contains,  however,  yet  other  substances  be- 
sides sugar  and  dextrine.  Rtiscliauer,  for  instance, 
found  in  a  malt-  and  hop-extract  42.6  sugar,  52.3  dex- 
trine, and  5.1  other  ingredients  (albumen,  alkalies, 
resin,  etc.).  In  the  proportion  found  by  Payen  of  52 
per  cent,  sugar  and  48  per  cent,  dextrine,  the  compo- 


THE   CHEMISTRY    OF    STARCH-SUGAR.  183 

sition  of  the  above  beer-malt  extract  would   appear 
thus : — 

49.3  per  cent,  sugar, 

45.6       u          dextrine,  and 
5.1       "          other  ingredients. 

If  the  dextrine  does  not  join  in  the  fermentation, 
then  we  obtain  after  the  fermentation  (whereby  from 
100  parts  glucose  51.11  parts  of  alcohol  are  produced, 
and  5.619  parts  of  yeast  are  separated) — 

From  49.3  per  cent,  sugar  .         .     25.2  alcohol. 

"      45.6       "          dextrine       .         .     45.6  dextrine. 
"        5.1       "          other  ingredients      2.9  residue. 

Let  us  now  compare  with  this  the  composition  of  a 
well,  but  by  no  means  yet  in  its  fermentation,  finished 
beer.  We  find,  for  example,  that  the  so-called  " Hof- 
Tyraiihausbeer"  in  Munich  contains  4.06  per  cent,  of  al- 
cohol and  5.55  per  cent,  of  extractive  substance;  the 
so-called  "St.  Marx  beer,"  of  Vienna,  5.75  percent, 
alcohol,  and  6.54  per  cent,  extractive  substance.  The 
still  better  fermented  Dutch  beers  furnish  yet  less 
extractive  substance. 

And  now  if  we  consider  that,  according  to  Payen, 
the  proportion  of  alcohol  to  dextrine  in  the  finished 
fermented  beer  must  be  as  1  to -1.92,  then  all  that  it 
missed  must  needs  belong  to  the  impossibilities. 

These  facts  furnish  ample  proof,  that  Payen's  doc- 
trine, that  the  dextrine  cannot  be  "decomposed"  or 
transformed  during  fermentation,  is  incorrect. 

It  is  cf  course  correct,  that  all  dextrine  is  never 
transformed  by  the  process  of  fermentation;  but  that  a 
very  considerable  part  of  the  dextrine  is  transformed  by 
the  fermentation  into  alcohol,  can  hardly  be  doubted, 
after  what  has  already  been  stated. 


184  MANUFACTURE    OF    STARCH,    ETC. 

On  the  Transformation  of  8tarcli  into  Sugar  by  means 
of  MaU7  Ity  Dulwunfaut. — Dubrunfaut  has  submitted 
to  the  French  Academy  of  Sciences,  an  interesting 
essay,  entitled  "  On  the  effect  of  malt  on  starch." 

1.  One  part  of  malt  which,  at  the  temperature  of  70° 
p.  (158°  F.),  has  no  noticeable  action  on  1000  parts  of 
starch,  is  capable  of  completely  liquefying  the  same 
quantity  of  starch  when  the  process  is  commenced  at 
50°  C.  (122°  F.)  or  below  this  temperature.     In  this 
case  a  complete  solution  ensues,  but  the  formation  of 
sugar  remains  incomplete.     If  the  process  takes  place 
at  a  temperature  of  25°  to  30°  C.  (77°  to  86°  F.),  then 
the  liquefying  is   less  complete  and  less  rapid,  while 
the  formation  of  sugar  is  stronger  and  more  perfect. 

2.  If  starch-paste  is  mixed  at  50°  C.  (122°  F.),  or 
even  at  a  lower  temperature,  with  1  part  of  malt,  this 
will  be  ample  to  change  100  parts  of  starch  as  com- 
pletely into  sugar  as  20  to  25  parts  of  malt  do  at  70° 
C.  (158°  F.). 

3.  One  part  of  malt  will  liquefy  100  parts  of  starch 
at  a  temperature  of  70°   C.   (158°   F.),   within   nine 
minutes;    but  in   this   temperature    the  formation  of 
su£ar  cannot  take  place  completely,  since  the  malt  in 
that  case  can  only  produce  three-quarters  of  the  result 
which  can  be  attained  under  the  most  favorable  condi- 
tions.    The  same  quantity  of  malt    causes  the  same 
quantity  of  starch    at  50°   C.   (122°   F.)   to   become 
liquid  within  twenty-five  minutes,  while,  at  a  tempera- 
ture of  from  25°  to  35°  C.  (77°  to  95°  F,),  the  solution 
becomes  complete  only  in  the  course  of  two  or  three 
hours.     In    the   two   latter  cases,  however,  a  perfect 
formation  of  sugar   ensues.     Of  course   the  time  re- 
quired for  this  varies.    At  30°  C.  (86°  F.),  it  ensues  less 
rapidly  than  at  50°  C.  (122°  F.),  but  without  noticeable 


THE    CHEMISTRY    OF    STARCH-SUGAR.  185 

difference,  as  to  the  completeness  of  the  formation  of 
sugar. 

4.  If  the  formation  of  sugar  is  produced  by  a  quan- 
tity of  malt  which,  in  comparison  to  that  of  the  starch, 
is  but  very  small,  then  the  final  result  will  be  the  more 
complete,  the  lower  the  temperature  which  has  pre- 
vailed at  the  trial,  while  the  same  small  amount  of  malt 
would,  at  a  temperature  of  between  53°.7  and  64°.4  C. 
(128°  and  148°  F.),  have  no  eflect  at  all,  as  is  for  instance 
the  case  by  the  application  of  0.001  part  of  malt.  In 
such  cases  a  larger  or  smaller  quantity  of  starch  fre- 
quently resists  the  action  of  the  malt  entirely,  i.  e.,  this 
part  does  not  even  become  liquefied,  and  still  less  con- 
verted into  sugar.  But  in  general  this  result  is  found 
by  otherwise  equal  conditions  to  a  large  extent,  occa- 
sioned principally  by  too  small  a  quantity  of  water 
taken  for  conversion.  If,  for  instance,  to  a  paste  pre- 
pared of  1  part  starch  and  20  parts  water,  is  added,  at 
40°  C.  (104°  F.)  or  at  a  still  lower  temperature,  0.01 
malt,  one-seventh  to  one-sixth  of  the  paste  will  entirely 
resist  the  transformation.  Thereby  the  remarkable 
phenomenon  appears,  that  this  unchanged  starch-paste, 
even  if  it  is  brought  in  contact,  under  the  most  favor- 
able conditions,  with  larger  quantities  of  malt,  can 
neither  be  caused  to  become  liquefied,  nor  made  saccha-* 
riferous,  while  it  is  still  affected  by  acids,  and  by  them 
partly  transformed  into  sugar.  According  to  this,  the 
starch  has  by  these  conditions  undergone  a  modifica- 
tion. Such  a  starch-paste  contains  more  azotic  than 
normal  starch.  Starch  at  70°  C.  (158°  F.),  mixed  into 
a  paste  with  fifty  times  its  weight  of  distilled  water, 
does  not  become  liquid,  even  when  the  paste  is  exposed 
for  several  days  to  the  influence  of  a  temperature  of 
50°  C.  (122°  F.). 


186  MANUFACTURE   OF   STARCH,    ETC. 

Cold  prepared  extracts  of  raw  barley,  wheat,  and 
rye  liquefy  and  saccharify  starch-paste  at  50°  C.  (122° 
F.)  completely,  while  in  a  temperature  of  70°  C.  (158° 
F.),  they  remain  without  producing  an  effect. 

DEDUCTIONS. 

If  we  now  sum  up  the  different  opinions,  as  set 
forth  by  Payen,  Musculus,  Dubrunfaut,  etc.,  with  re- 
gard to  the  formation  of  dextrine,  and  the  transforma- 
tion of  starch  into  starch-sugar  and  dextrine,  we  will 
come  to  the  conclusion — 

1.  That  starch,  by  being  torrefied  in  a  temperature 
not  exceeding  180°  to  200°  C.  (356°  to  392°  F.),  is 
in  a  preponderating  degree  transformed  into  dextrine. 

2.  If  the   starch   is   heated  with   diluted   acids,   it 
changes  in  the  first  place  into  soluble  starch,  which 
is    then    transformed  into  starch-sugar  and  dextrine. 
The  quantity  of  the  sugar  forming  depends  on  the  con- 
centration of  the  acids,  and  increases  during  the  period 
of  its  action  considerably,  while,  as  will  be  obvious, 
the  amount  of  the  dextrine  at  the  same  time  decreases. 

3.  If  the  starch  is  heated  with  a  solution  of  diastase 
(extract  of  malt),  it  will  likewise  at  first  change  into 
soluble  starch,  of  which  thereupon  the  larger  part  is 
first  turned  into  dextrine  and  a  lesser  part  into  sugar. 
The  quantity  of  the  forming  starch-sugar  will  depend 
above  all  on  the  temperature  under  which  the  diastase 
operates.     A  larger  quantity  of  sugar  is  formed  at  a 
temperature  of  from  60°  to  65°  C.  (140°  to  149°  F.),  this 
being  the  most  suitable  temperature  for  the  formation 
of  sugar,  but  at  increased  temperatures,  say  at  65°  to 
75°  C.  (149°  to  167°  F.),  larger  quantities  of  dextrine 


THE    CHEMISTRY    OF    STARCH-SUGAR.  187 

are  formed,  until  finally,  by  a  continued  increase  of 
temperature,  the  diastase  itself  is  destroyed. 

The  sugar  formation  increases  during  the  action,  by 
the  diminution  of  the  dextrine,  especially  when  the 
sugar  formed  is  caused  to  ferment  by  yeast,  and  is 
thereby  removed.  The  quantity  of  the  formed  sugar 
exceeds,  even  in  the  most  favorable  cases,  the  amount 
of  the  dextrine  but  little. 

CHEMICAL  PROPERTIES.     ACTION.     DECOM- 
POSITION. 

Mitscherlich  had  already  promulgated  the  doctrine, 
that  starch-sugar  as  well  as  fruit-sugar  by  fermentation 
changes  at  once  into  alcohol  and  carbonic  acid,  with- 
out previously  passing  through  an  intermediate  state. 
This  opinion  has  been  verified  and  sustained  by  chemists 
of  a  later  period.  Cane-sugar,  on  the  other  hand,  can- 
not be  fermented  immediately;  it  must  first  pass  into 
the  condition  of  starch-sugar  before  it  can  undergo 
the  process  of  alcoholic  fermentation.  But  it  is  not 
necessary  for  the  cane-sugar  to  be  previously  entirely 
transformed  into  starch-sugar;  but  this  transformation 
takes  place  very  gradually,  and  in  the  same  ratio  as 
fermentation  itself  progresses. 

When  cane-sugar  and  starch-sugar  are  simultane- 
ously exposed  to  the  action  of  yeast,  the  fermentation  of 
the  grape-sugar  ensues  very  soon  at  20°  C.  (68°  F.) ; 
while  in  the  solution  of  cane-sugar,  even  after  the  lapse 
of  a  month,  no  alcoholic  formation  is  noticed  even  if 
the  temperature  is  increased  to  25°  or  40°  C.  (77°  or 
104°  F.).  Only  by  increasing  the  amount  of  yeast 
sixfold  (to  9.42  grammes  for  35  grammes  of  sugar 
=  145.35  grains  for  540  grains  of  sugar)  does  the  fer- 


188  M ANUFACTUKE    OF    STARCH,    ETC. 

mentation  begin  at  last,  and  then  but  slowly,  because 
the  transformation  of  the  cane-sugar  into  starch-sugar 
has  been,  so  to  say,  forced  by  the  large  quantity  of 
yeast.  The  further  assertion  of  later  chemists,  that 
to  the  cane-sugar  need  only  be  added  some  cream* 
of  tartar,  in  order  to  facilitate  the  process  of  fermen- 
tation, is  entirely  confirmed.  Of  course,  this  occurs 
in  consequence  of  its  transformation  into  starch-sugaiv 
We  can,  therefore,  in  general  state  that  cane-sugar 
in  its  unaltered  condition  is  not  fermentable,  but  will 
easily  change  into  direct  fermentable  starch-sugar 
and  also  into  fruit-sugar,  since  the  mere  contact  with 
yeast,  or  the  heating  with  a  few  drops  of  muriatic  acid 
suffices  for  this  purpose. 

The  solutions  of  grape-sugar  are  decomposed  by  the 
action  of  the  yeast;  the  sugar  separates  and  furnishes 
the  usual  products  of  the  alcoholic  fermentation,  i.  e., 
alcohol  and  carbonic  acid,  besides  some  other,  less 
important  products. 

Grape-sugar  is  more  soluble  in  alcohol  than  cane- 
sugar,  since  100  weight  parts  of  absolute  alcohol  will 
dissolve  1.66  weight  parts  of  grape-sugar  completely 
(alcohol  of  83  per  cent,  dissolves  18  parts  of  starch- 
sugar).  But  in  water  grape-sugar  is  less  soluble  than 
cane-sugar,  and  requires  for  its  solution  1|  parts  of  its 
weight  of  cold  water.  In  boiling  water  it  is  soluble 
in  all  conditions,  and  forms  a  sweet  syrup  which,  how- 
ever, cannot  be  drawn  into  threads  like  the  syrup  of 


cane-sugar. 


By  increasing  the  heat  from  200°  to  220°  C.  (392°  to 
428°  F.)  the  starch-sugar  is  changed  into  glucosan  or 
caramel,  and  other  products  of  a  brown  color. 


THE  CHEMISTRY  OF  STARCH-SUGAR.         189 

CHEMICAL  COMBINATIONS. 

Starch-sugar  is  dissolved  by  concentrated  sulphuric 
acid  and  with  it  forms  a  double  acid:  Starch-sugar~ 
sulphuric  acid,  which  furnishes,  combined  with  lime  and 
barium,  soluble  salts.  If  grape-sugar  is  continuously 
boiled  with  diluted  sulphuric  acid  or  with  muriatic 
acid,  it  is  changed  gradually,  i.  e.,  is  decomposed,  and 
the  product  is  no  longer  fermentable. 

Starch-sugar  enters  into  combinations  with  alkalies 
and  alkaline  earths,  which  however  are  not  very  con- 
stant, even  at  a  common  temperature,  but  very  readily 
become  decomposed.  This  decomposition  ensues  al- 
most instantly  at  an  increased  temperature,  and  the 
solutions  of  these  salts  are  colored  at  a  temperature  of 
70°  C.  (158°  F.)  yellowish-brown,  and  at  the  boiling 
point,  with  admission  of  the  atmosphere,  black.  This 
is  caused  by  the  formation  of  an  organic  acid  (glucic 
acid)  produced  by  the  action  of  the  alkalies  on  the 
sugar. 

Another  chemical  combination  ensues  of  starch- 
sugar  and  hydrate  oxide  of  copper,  which  is  demon- 
strated by  Fehling's  alkaline  solution  of  copper,  and 
its  action  on  grape-sugar,  which  we  use  to  de- 
termine the  quantitative  proportion  of  grape-sugar. 
This  combination  forms  a  precipitate,  which,  being 
dried  in  the  air,  forms  a  bluish-green  powder,  partly 
soluble  in  alkali.  When  the  proportion's  are  accurately 
observed,  the  filtered  liquid  contains  neither  grape- 
sugar  nor  copper. 

For  practical  purposes,  the  most  important  of  all 
the  chemical  compounds  grape-sugar  forms  is  that 
with  chloride  of  sodium  (culinary  salt),  forming  thus 
the  so-called  chloride  of  sodium  glucose. 


190  MANUFACTURE   OF   STARCH,   ETC. 

This  chemical  combination,  so  very  suitably  em- 
ployed for  preserving  various  articles  of  food  (meat, 
butter,  milk,  wine,  beer,  and  vegetables),  we  will  eluci- 
date more  fully  in  the  course  of  this  treatise. 


THE    TECHNOLOGY   OF    STARCH-SUGAR.  191 


SECTION  II. 

THE  TECHNOLOGY  OF  STARCH-SUGAR. 

THE  MANUFACTURE  OF  STARCH-SUGAR. 

Genwal Introduction. — It  has  already  been  stated  that 
grape-sugar,  as  well  as  grape-sugar  syrup,  commonly 
called  glucose — whose  manufacture  somewhat  later  had 
been  recommended  by  the  application  of  malt,  after  a 
clearer  idea  had  been  attained  of  the  process  of  the 
sugar  formation  by  means  of  diastase — for  a  long  time 
failed  to  enjoy  the  desired  development.  The  syrup  of 
starch-sugar  then  only  attracted  the  merited  attention, 
when  the  want  of  the  East  India  syrup  made  itself  felt 
in  Europe,  as  a  consequence  of  the  propagation  of  the 
manufacture  of  beet-sugar.  The  beet-sugar  manufac- 
tories or  refining  establishments  furnish,  as  is  known, 
an  article  similar  to  the  East  India  loaf-sugar,  but  they 
fail  to  furnish  a  syrup  which  is  identical  with  that  from 
the  East  Indies.  For  this  reason  glucose  was  com- 
menced to  be  manufactured  in  large  quantities,  partly  as 
a  substitute  for  the  India  syrup,  and  partly  for  an  ad- 
mixture with  the  East  India  product,  and  thus  to  cover 
the  deficiency  of  this  syrup.  In  this  country  the  ad- 
mixture of  glucose  with  cane-syrup  is  principally  done 
to  improve  the  color  and  body  of  the  latter.  The  solid 
starch-sugar,  too,  found  afterwards  the  merited  con- 
sideration; again,  in  order  to  bring  up  the  quantity  of 
sugar  in  the  grape-juice  (must)  of  a  poor  wine  year,  and 


192  MANUFACTURE    OF    STARCH,    ETC. 

for  reducing  (gallesizing*)  the  contents  of  acid,  and 
also  for  the  purpose  of  increasing  the  quantity  of  wine 
correspondingly  (petiotizingf).  For  the  preparation  of 
other  wines  (fruit-wines),  and  for  the  distillation  of 
brandies  from  fermented  liquors,  starch-sugar  is  like- 
wise used,  and  also  in  considerable  quantities  for  the 
production  of  usugar-couleur." 

Grape-sugar  finds  no  application,  which  common 
sugar  (crystallizing  sugar)  could  not  supply;  starch- 
sugar  must  always  be  considered  as  being  a  substitute 
for  crystallizing  sugar.  Hence  it  follows,  that  the 
manufacture  of  starch-sugar  is  only  advantageous 
when  it  can  be  produced  more  cheaply  than  cane- 
sugar  or  beet-sugar.  Besides  the  price  of  the  crystal- 
lized sugar  that  of  the  starch,  or  what  amounts  to  the 
same  the  value  of  the  starch-containing  materials,  is  a 
matter  of  first  consideration.  When  we  consider  that 
the  article  represented  in  commerce  as  starch-sugar  is 
very  often  far  from  being  pure  grape-sugar,  containing 
upwards  of  50  per  cent,  water  and  substances  which 
are  not  fermentable,  we  are  led  to  believe  that  starch- 
sugar  is  more  used  than  is  profitable,  and  would  ad- 
vise the  consideration  not  merely  of  the  price  of  the 
article,  but  also  of  its  quality. 

The  transformation  of  starch  into  sugar  by  means  of 
sulphuric  acid  and  diastase  (malt)  has  already  been 
explained  in  a  former  chapter.  If  starch  is  boiled  in 
water  containing  sulphuric  acid,  there  will  be  pro- 
duced from  the  starch,  in  the  first  place,  soluble  starch 

*  Gall,  a  celebrated  chemist,  has  made  himself  meritorious  by 
improving  wine  by  this  process;  hence  it  is  named,  after  him,  the 
"  Gallesizing"  process. 

•j*  To  increase  the  quantity  of  wine  by  this  means  was  recom- 
mended by  Petiot,  and  hence  this  method  is  called  "petiotizing." 


THE   TECHNOLOGY    OF    STARCH-SUGAR.  193 

(amiduliri);  from  this"  is  formed  by  continued  boiling, 
starch-gum  (dextrine-gum)  and  starch-sugar  (glucose), 
and  if  the  boiling  is  continued  sufficiently  long,  an 
almost  complete  transformation  of  gum  into  sugar 
takes  place,  i.  e.,  the  liquid  contains  besides  the  sul- 
phuric acid  (which  remains  unchanged)  almost  nothing 
else  but  starch-sugar. 

The  process  of  transformation  can  be  followed  up  by 
means  of  a  solution  of  iodine  and  by  alcohol.  The 
liquid  will  prove  to  contain  no  more  soluble  starch, 
nor  any  of  the  above-mentioned  intermediate  products, 
as  soon  as  a  cooled-off  sample  thereof  is  no  longer 
colored  reddish  or  blue  by  applying  a  solution  of 
iodine.  When  this  point  is  reached  the  liquid  will, 
when  mixed  with  a  larger  quantity  of  alcohol,  precipi- 
tate a  white  mass  of  dextrine.  By  still  continuing 
the  boiling,  the  quantity  of  the  precipitate  decreases, 
until,  at  last,  by  a  test  with  alcohol,  no  further  pre- 
cipitation ensues.  Formerly  it  was  accepted  that,  at 
this  juncture  all  starch-gum  had  been  transformed  into 
sugar,  and 'that  the  liquid  then  contained  naught  but 
starch-sugar.  But  according  to  Anthon,  an  authority 
on  this  subject,  this  is  not  the  case.  The  presence  of 
a  larger  quantity  of  sugar  besides  the  gum,  either  pre- 
vents the  precipitation  of  the  latter  by  alcohol,  or  an 
intermediate  product  is  formed,  which  is  not  precipi- 
tated by  it. 

Starch-gum  (dextrine)  is  indissoluble  in  alcohol,  and 
is  by  absolute  alcohol  precipitated  from  its  aqueous 
solution.  The  complete  transformation  of  starch  into 
sugar  cannot  be  determined  with  certainty  by  alcohol. 
The  non-observance  of  this  fact  is  the  cause  of  the 
grape-sugar  of  commerce  being  frequently  far  from 
pure  sugar.  Only  by  dint  of  long-continued  boiling  is 


O?  THE 


194  MANUFACTURE   OF    STARCH,    ETC.        . 

the  object  effected  of  having  the  liquid  contain  almost 
nothing  else  but  starch-sugar. 

The  relative  quantity  of  sulphuric  acid  used  is  of 
importance,  as  the  duration  of  time  for  a  conversion  is 
dependent  upon  it. 

The  transformation  occurs,  for  instance,  much  more 
rapidly  when  two  per  cent,  of  sulphuric  acid  is  added 
to  the  starch  than  when  but  one  per  cent,  acid  is  ap- 
plied. By  the  boiling  with  an  increased  pressure,  too, 
the  time  of  the  operation  is  shortened.  The  sulphuric 
acid  remains  unchanged  by  the  process ;  but  we  are 
not  yet  in  a  condition  to  give  a  full  explanation  of  its 
action.  It  can  be  removed  from  the  saccharine  liquid 
by  carbonate  of  lime.  According  to  calculation  every 
100  kg.  (220  Ibs.)  of  dry  starch  should  furnish  108  kg. 
(238  Ibs.)  of  dry  sugar,  corresponding  to  120  kg.  (264 
Ibs.)  of  crystalline  starch-sugar,  that  is,  if  the  trans- 
formation into  sugar  were  a  perfect  one. 

We  again  most  emphatically  assert,  that  a  complete 
transformation  of  starch  or  dextrine  into  starch-sugar 
can  never  occur  in  practice.  Anthon  has  proven  that 
a  perfect  transformation  of  starch  into  sugar  could  only 
occur  at  that  point  of  time  (for  instance  after  the  lapse 
of  36  hours  or  even  longer)  when,  by  the  simultaneous 
action  of  the  sulphuric  acid  upon  the  sugar  that  had 
been  formed  many  hours  previously,  large  quantities 
of  other  products  accumulate  in  the  sugar  solution. 
But  in  such  a  case  there  would  be  not  only  nothing 
gained,  but  the  matter  would  be  rendered  even  worse, 
since  the  products  of  decomposition  thus  formed  would 
be  of  greater  injury  for  all  possible  uses  of  starch- 
sugar  than  the  small  quantities  of  dextrine  would  be, 
which  might  be  retained  in  the  finished  article. 

By  a  too  long-continued  boiling  of  the  starch  with 


THE   TECHNOLOGY    OF    STARCH-SUGAR.  195 

sulphuric  acid  an  entirely  useless  product  would  be 
obtained. 

The  transformation  of  starch  into  starch-gum  and 
starch-sugar  by  diastase  (malt),  occurs  most  rapidly 
and  completely  at  the  so-called  mash  temperature  of  60° 
to  65°  C.  (140°  to  149°  F.).  The  formation  of  soluble 
starch  in  this  case  takes  place  but  during  a  very  short 
period.  Starch-gum  and  sugar  ensue  simultaneously, 
and  it  is  not  possible  that  the  starch-gum  itself  can  be 
completely  transformed  into  sugar  even  by  a  continued 
action  of  the  diastase.  Hence  a  product  results  which 
always  besides  sugar  still  contains  a  considerable  quan- 
tity of  starch-gum.  But  if  to  the  solution  thus  obtained 
some  sulphuric  acid  is  yet  added  (about  1  per  cent.) 
and  then  boiled,  an  approximately  complete  trans- 
formation of  the  starch-gum  into  sugar  will  take  place, 
especially  if  the  boiling  is  done  under  pressure. 

From  these  general  introductory  remarks  the  follow- 
ing results  for  practice  are  gleaned :  Pure,  solid,  hard 
crystalline  starch-sugar  can  only  be  produced  by  means 
of  sulphuric  acid,  and  only  by  a  long-continued  boil- 
ing. By  a  less-continued  boiling  of  the  starch  in  sul- 
phuric acid  water,  a  glucose  is  produced  which  con- 
tains considerable  quantities  of  starch-gum  (or  an 
intermediate  product  between  gum  and  sugar).  The 
sugar  thus  obtained  is  not  hard  and  crystalline,  but  soft 
and  tough,  and  becomes  moist  in  the  air.  From  a 
syrup  thus  produced,  by  a  not  so  long-continued  boil- 
ing, no  solid  sugar  separates,  because  the  starch-gum 
prevents  the  separation.  In  a  syrup  obtained  by  a 
long-continued  boiling,  ensues  in  time,  a  separation  of 
starch-sugar  in  a  grainy  condition.  This  is  not  a  de- 
sirable product,  and  is  considered  as  spoiled  glucose. 
Syrup  prepared  by  means  of  malt  alone  contains  a  con- 


196  MANUFACTURE   OF   STARCH,    ETC. 

siderable  amount  of  starch-gum.  By  the  application 
of  sulphuric  acid,  after  the  use  of  malt,  the  gum  can 
be  transformed  in  a  great  measure  into  sugar.  Grape- 
sugar  can  be  made  directly  from  potatoes,  grain,  rice, 
maize,  moss,  wood,  fruits,  honey,  raisins,  etc. 

In  the  manufacturing  industries,  starch-sugar,  or 
grape-sugar,  and  glucose  made  of  starch  only  find  con- 
sideration, and  hence  we  will  here  treat  more  promi- 
nently the  subject  of  the  conversion  of  starch  into 
grape-sugar. 

THE  MANUFACTURE  OF  GLUCOSE  AND  STARCH- 
SUGAR  FROM  STARCH. 

For  producing  glucose  and  grape-sugar  from  starch 
on  a  large  scale,  sulphuric  acid  serves  almost  exclu- 
sively, while  malt  (diastase)  finds  only  application  for 
the  manufacturing  of  glucose,  and  this  even  only  in 
some  isolated  cases.  Pure,  solid,  hard  crystallizing 
sugar  can  only  be  produced  by  means  of  sulphuric 
acid,  and  by  dint  of  continued  boiling  and  by  further 
refining  of  the  first  product  (the  stiff  or  coagulated 
sugar  mass),  yielded  by  this  method.  Meanwhile  the 
transformation  of  starch  into  sugar  will  be  consider- 
ably forwarded  by  adding  to  the  sulphuric  acid  a  small 
quantity  of  nitric  acid.  If  the  sulphuric  acid  does  not 
act  upon  the  starch  for  a  sufficient  length  of  time  (by  a 
too  short  boiling  of  the  starch  with  the  acid),  a  syrup 
will  be  obtained  which  yet  contains  very  considerable 
quantities  of  dextrine.  From  this  syrup  no  solid  sugar 
will  separate,  since  its  ability  to  crystallize  is  checked 
by  the  presence  of  the  dextrine.  The  product  yielded — 
still  absorbing  moisture  from  the  atmosphere — will  re- 
main soft,  tough,  and  smeary.  By  a  too  long-continued 


THE    TECHNOLOGY    OF    STARCH-SUGAR.  197 

« 

boiling  of  the  starch  in  sulphuric  acid  water,  however, 
the  sugar  will  separate  in  a  granulated  condition, 
which  is  not  desirable,  and  must  also  be  regarded  as  a 
mistake  of  the  manufacturer,  except  when  the  final  re- 
sult was  intended  for  granulated  sugar. 

By  an  exclusive  application  of  malt  for  manufactur- 
ing starch-sugar  a  pure  article  is  never  produced,  be- 
cause a  considerable  portion  of  the  dextrine  formed  by 
the  starch  remains  unchanged;  and  the  complete  trans- 
formation of  the  same  into  sugar  occurs  only  by  apply- 
ing sulphuric  acid  after  the  malt  has  been  used. 

Starch-sugar  produced  from  starch  appears  in  com- 
merce in  five  different  forms,  viz.:  1,  as  starch-syrup; 

2,  as  a  sticky  mass,  termed  "  imponderable  syrup  ;"* 

3,  as  granulated  sugar  ;  4,  as  common,  solid  sugar  (stiff 
or   congelated   sugar-mass) ;    and  5,  as  refined,  solid, 
starch-sugar  (distinguished  by  its  whiteness  and  sweet 
taste,  which  are  secured  by  refining  through  boneblack). 

The  species  of  starch  applied  in  the  United  States 
for  the  manufacture  of  starch-sugar  is  with  but  few 
exceptions  almost  always  corn-starch.^ 

THE  MANUFACTURE  OF  GLUCOSE-SYRUP  AND 
STARCH-SUGAR  FROM  STARCH  BY  MEANS  OF 
SULPHURIC  ACID. 

The  manufacture  of  starch-syrup  or  glucose  and 
starch-sugar  by  means  of  sulphuric  acid  is  divided  into 
the  following  operations  : — 

The  boiling  of  the  starch  in  sulphuric  acid  water. 

The  removal  of  the  sulphuric  acid  and  the  gypsum 
produced  thereby  from  the  solution. 

Evaporating  and  refining  of  the  sugar  solution. 

*  Generally  termed  glucose  in  this  country, 
f  In  Europe  it  is  potato-starch. 


198  MANUFACTURE   OF    STARCH,    ETC. 

m 

These  labors  are  performed  in  the  glucose  manufac- 
tories in  very  various  ways,  and  by  the  application  of 
the  most  diverse  mechanisms.  Almost  every  establish- 
ment has  its  peculiar  modus  operandi.  It  should  be 
further  mentioned  that  in  using  corn-starch  a  some- 
what larger  quantity  of  sulphuric  acid  is  advisable  for 
the  conversion. 

The  Process  of  Boiling. — The  boiling  of  the  starch 
in  the  water  containing  sulphuric  acid  is  mostly  and 
best  performed  in  a  wooden  vessel  (a  vat  or  barrel 
rather  higher  than  wide)  by  a  direct  admission  of  steam. 
This  method  has,  however,  the  disadvantage  of  bring- 
ing too  much  water  into  the  decoction.  The  lining  of 
the  vessel  with  lead  is  not  necessary,  but  increases 
its  durability.  For  manufacturing  on  a  smaller  scale 
a  perfectly  scoured  copper  kettle  may  serve,  which  can 
be  heated  over  a  direct  fire. 

With  regard  to  the  construction  of  the  boiling  vat 
the  following  directions  are  to  be  observed : — 

The  starch-boiling  vats  were  formerly  constructed 
in  such  a  manner  that  they  could  be  heated  with  pres- 
sure. These  vats  were  able  to  bear  a  great  pressure, 
similar  to  that  of  a  steam-boiler,  with  safety-valve, 
manometer,  and  air-valve.  But  despite  all  these  pre- 
cautions vats  thus  constructed  offered  but  very  little 
security,  and  it  often  occurred  that  by  dint  of  the 
higher  steam  pressure  the  bottom  of  such  vats  would 
be  blown  out,  thereby  frequently  causing  great  loss  of 
life.  Such  vats  exist  even  yet  in  some  few  of  the  older 
establishments,  but  are  no  longer  used  in  manufactories 
of  more  recent  construction.  The  only  advantage 
which  these  vats  of  old  construction  offered  was,  that 
the  process  of  boiling  was  somewhat  shortened;  but 
they  had  the  fault,  that  the  starch  therein  became  some- 


THE   TECHNOLOGY    OF    STARCH-SUGAR. 


199 


what  thin  and  liquidy,  because  the  steam  entering  into 
the  mass  in  a  direct  way  became  condensed,  diluting 
the  mass  down  to  14°  to  15°  B. 

In  the  modern  stirring  tub  (see  Fig.  28),  on  the  other 
hand,  a  spiral  pipe  or  worm  made  of  copper  is  inserted 
through  which  the  steam  circulates.  By  this  means 
the  mass  is  brought  to  a  boil,  without  being  diluted, 
so  that  the  same,  after  having  done  boiling,  is  usually 
of  19°  to  20°  B. 

Fig.  28. 


Stirring  tub. 

A  great  saving  of  fuel  is  one  of  the  advantages 
gained,  since  5°  less  is  to  be  concentrated.  The  entire 
labor  with  this  new  apparatus  is  very  simple,  and  not 
at  all  dangerous. 

The  following  is  an  accurate  description  of  such  a 
boiling  apparatus : — 

The  staves  for  the  vat  are  to  be  of  good  pine  wood, 
6.67  centimetres  (2.63  inches)  thick.  The  vat,  in  order 
to  allow  a  boiling  twice  a  day  of  1500  kilogrammes 
(3300  Ibs.)  of  green  starch,  should  be  2.5  metres  (8.2 


200  MANUFACTURE    OF    STARCH,    ETC. 

feet)  in  height.  Its  diameter  below  is  1.75  metres 
(5.74  feet),  and  above  1.67  metres  (5.48  feet)  ;  it  is  open 
above,  with  a  cover  to  be  laid  on,  and  supplied  with  a 
chimney  or  funnel.  The  lid  or  cover  consists  of  five 
or  six  parts,  as  it  would  otherwise  be  too  heavy;  the 
funnel  stands  firmly  upon  the  right  side,  and  this  part 
is  fastened  to  the  boiling  vat.  The  chimney  is  square, 
and  is  made  of  2  centimetres  (0.79  inch)  thick  pine 
boards,  has  a  width  of  26.67  centimetres  (10.5  inches) 
in  the  clear,  and  is  of  such  a  height  as  to  project  over 
the  roof  of  the  establishment,  in  order  to  carry  off  the 
odor.  The  vat'is  placed  upon  a  strong  framework,  of 
sufficient  height  that  the  boiled  starch  can  run  into 
the  neutral izing-coops  by  means  of  spigots,  which  are 
placed  above  the  bottom  of  the  vat. 

The  copper  worm  has  five  or  six  windings  or  less, 
according  to  its  heating  surface,  and  should  have  only 
a  diameter  of  1.4  centimetres  (0.55  inch),  so  that  it 
may  be  inserted  into  the  vat  without  trouble.  The 
copper  pipes,  which  are  used  for  the  construction 
of  the  worm,  have  a  diameter  of  6.67  centimetres 
(2.63  inches),  and  the  rings  are  fastened  with  brass 
clamps.  In  the  construction  of  the  worm  nothing 
must  be  made  of  iron;  all  screws  and  nuts  must  be 
of  copper  or  brass,  since  iron  will  be  dissolved  by  the 
acid  containing  substances.  The  worm  is  placed  hori- 
zontally upon  the  bottom  of  the  boiling-vat;  the  steam 
is  carried  to  the  worm  through  a  pipe,  which  is  affixed 
in  the  vat.  The  condensed  water  (the  exhaust)  escapes 
at  the  side  through  a  pipe  of  1.75  centimetres  (0.69 
inch)  being  connected  with  the  copper  worm  through 
the  wood  of  the  boiling  vessel  and  carried  to  the  feeding 
apparatus  of  the  steam  boiler.  The  requisite  quantity 
of  water  is  placed  in  the  vat,  heating  it  to  a  boil,  but 


THE   TECHNOLOGY    OF    STARCH-SUGAR.  201 

before  this,  adding  the  previously  dilated  sulphuric 
acid.  Thereupon  the  starch,  which  has  been  mixed  in 
lukewarm  water  until  it  has  acquired  a  milky  consist- 
ency, is  gradually  left  to  run  into  the  vat  from  the 
stirring  tub,  as  shown  by  Fig.  28,  while  the  liquid  in 
the  boiling  tub  is  kept  at  a  constant  boil.  It  is  there- 
fore most  convenient  for  this  purpose  to  place  a  stir- 
ring-vat, supplied  with  a  stopcock,  over  the  boiling- 
vat,  the  stirring-vat  containing  the  starch-milk.  The 
flowing  of  the  starch-milk  must  be  so  regulated  that 
the  liquid  in  the  boiling  vessel  does  not  cease  to  boil, 
and  that  a  paste  formation  does  not  ensue,  or  at  least 
be  but  of  a  transient  nature.  Inasmuch  as  the  starch 
deposits  itself  quickly  from  the  starch-milk,  it  must 
while  it  flows  in  be  constantly  stirred,  for  which  pur- 
pose a  stirring  apparatus  may  be  placed  in  the  vessel. 
Instead  of  permitting  the  starch-milk  to  flow  in  con- 
stantly, the  flow  is  occasionally  interrupted,  and  this 
must  needs  be  done,  if  the  liquid  in  the  boiling  ap- 
paratus does  not  continue  to  boil,  and  in  consequence 
of  a  formation  of  paste  becomes  thickened.  The  larger 
the  quantity  of  the  boiling  liquid  is,  the  less  readily 
it  will  cease  boiling,  and  the  less  a  paste  formation 
will  ensue.  If  no  stirring-vat  for  the  starch-milk 
is  placed  over  the  boiling  apparatus,  the  starch  milk 
must  be  poured  into  the  boiling  sour  water  in  portions. 
To  each  100  kilogrammes  (220  Ibs.)  of  air-dry  starch 
from  150  to  200  litres  (39.6  to  52.8  galls.)  of  water, 
and  generally  2  kilogrammes  (4.4  Ibs.)  of  sulphuric  acid 
are  used,  when  glucose  is  to  be  produced ;  for  the 
manufacture  of  solid  sugar,  the  amount  of  acid  may 
be  increased  to  4  kilogrammes  (8.8  Ibs.),  in  order 
also  to  shorten  the  time  of  boiling.  In  the  amount  of 
water  stated,  the  water  for  stirring  the  starch  is  in- 


202  MANUFACTURE   OF    STARCH,    ETC. 

eluded,  and  hence  the  entire  amount  of  the  water  is 
not  placed  in  the  boiling  vessel,  but  as  much  less  as  is 
already  contained  in  the  starch-milk.  Meantime  it 
should  not  be  deemed  necessary  to  scrupulously  adhere 
to  the  prescribed  quantity  of  water,  a  little  more  or  less 
is  of  little  consequence,  but  the  worm  in  the  converter 
must  be  covered.  Inasmuch  as  the  starch  used  in  glu- 
cose factories  is  generally  also  prepared  therein,  and 
since  the  moist  (green)  starch  can  be  well  preserved 
in  vats  and  barrels,  the  starch  is  most  generally  applied 
in  a  moist  condition ;  and  hence,  instead  of  using  200 
kilogrammes  (440  Ibs.)  of  dry  starch  300  kilogrammes 
(660  Ibs.)  of  green  starch  are  taken,  that  is,  one-half 
more  than  is  taken  of  the  dry  article.  The  amount  of 
water  contained  in  the  green  starch,  is  of  course  counted 
in  with  the  amount  of  water,  which  is  applied  for  the 
mixing  of  the  same. 

Respecting  the  boiling  by  steam,  it  should  be  re- 
marked, that  the  quantity  of  the  water,  which  is  poured 
in  a  cold  state  into  the  boiling  apparatus,  will  increase 
about  one-fifth  by  heating  to  a  boil,  and  that  even 
during  the  process  of  boiling  an  increase  of  the  liquid 
ensues.  By  boiling  over  a  direct  fire,  the  liquid  di- 
minishes constantly  by  evaporation,  and  thus  neces- 
sitates the  replacing  the  evaporated  water  from  time 
to  time  with  pure  boiling  water. 

After  the  entire  quantity  of  the  starch-milk  has  run 
in  or  is  poured  in,  the  boiling  is  continued  until  the 
intended  transformation  is  accomplished.  If  glucose 
is  to  be  produced,  the  boiling  process  is  of  shorter 
duration  than  in  the  case  of  manufacturing  solid  sugar, 
in  which  case  the  quantity  of  the  sulphuric  acid  to  be 
applied  is  to  be  larger. 

During  the  boiling  of  the  starch  with  sulphuric-acid 


THE   TECHNOLOGY    OF    STARCH-SUGAR.  203 

water,  a  very  disagreeable,  penetrating  odor  is  devel- 
oped, which  becomes  quite  unbearable  to  the  vicinity.* 

At  short  intervals  the  liquid  is  tested,  first  with  a 
solution  of  iodine,  and  afterwards  with  alcohol.  For 
the  test  with  a  solution  of  iodine,  a  few  .drops  of  the 
liquid  are  placed  in  a  test-tube,  diluting  the  same  with 
cold  water,  then  adding  a  few  drops  of  the  solution  of 
iodine.  "Whenever  the  liquid  is  no  longer  colored 
violet  or  reddish  by  the  reagent,  the  transformation 
into  gum  and  sugar  is  finished.f  When  this  point  is 
reached  the  test  with  alcohol  begins.  A  few  teaspoon- 
fuls  of  the  liquid  are  now  placed  in  the  test-tube,  and 
an  equal  or  double  quantity  of  the  volume  of  strong 
alcohol  is  added.  The  stronger  the  white  separation 
caused  thereby  appears,  the  larger  is  the  quantity  of 
the  starch-  or  dextrine-gum  still  present.  If  the  pre- 
cipitation by  means  of  alcohol  finally  ceases,  the  starch- 
gum  is  nevertheless  not  entirely  changed  into  sugar. 
A  secure  and  simple  means  for  determining  the  com- 
plete transformation  into  sugar  is  not  yet  known. 

The  ^Removal  of  the  Sulphuric  Acid;  Process  of 
Neutralization. — As  soon  as  the  intended  transforma- 
tion of  the  starch  is  attained  by  means  of  a  sufficiently 
long  boiling,  the  sulphuric  acid  is  to  be  removed  from 
the  liquid.  This  is  accomplished  by  the  application 
of  carbonate  of  lime.  The  sulphuric  acid  decomposes 
the  lime,  and  under  a  lively  efflorescence  the  car- 
bonic acid  gas  escapes,  and  insoluble  sulphate  of  lime 
(gypsum)  is  produced.  The  liquid  thereby  loses  its 
acidy  reaction  and  becomes  neutral.  This  operation 

*  This  refers  principally  to  potato-starch,  as  corn-starch  does  not 
contain  so  much  fusel  oil. 

t  The  product  thus  obtained  is  glucose. 


204  MANUFACTURE   OF    STARCH,   ETC. 

can  be  accomplished  in  the  boiling  apparatus  itself.  In 
most  cases,  however,  this  operation  is  performed  in 
neutralizing  vats.  Such  a  vat  is  a  flat  vessel,  whose 
height  stands  to  its  width  in  a  proportion  of  1  to  3. 
The  neutralizing  in  the  boiling  vat,  although  feasible 
is,  nevertheless,  troublesome,  as  that  vessel  will  have 
to  be  washed  out  previous  to  each  new  operation. 

The  most  suitable  carbonate  of  lime  for  the  process 
of  neutralization  is  chalk,  but  even  pure  limestone, 
when  free  from  clay,  can  be  applied  for  this  purpose. 
But  it  is  indispensable  to  grind  these  articles  into  a 
fine  powder.  Of  this  powder  a  handful  is  thrown  at  a 
time  into  the  hot,  acidy  liquid,  by  constant  stirring 
with  a  paddle  and  mixed  until  no  further  ebullition 
ensues.  If  too  much  is  thrown  in  at  once  it  might 
involve  the  danger  of  overrunning.* 

For  each  kilogramme  (2.2  Ibs  )  of  sulphuric  acid 
contained  in  the  liquid,  one  kg.  of  pure  carbonate  of 
lime  is  required  for  neutralizing.  But  of  chalk  and 
limestone  something  more  must  be  taken,  since  these 
articles  are  not  entirely  pure  carbonate  of  lime.  An 
excess,  howrever,  has  to  be  avoided,  in  order  not  to 
unnecessarily  increase  the  sediment. 

The  diminution  of  the  acidy  reaction  during  the 
adding  of  the  carbonate  of  lime,  can  be  tested  by  litmus 
paper — the  paper  becomes  gradually  less  reddened.  As 
soon  as  the  paper  shows  a  perceptible  decrease  of  the 
sour  reaction,  the  liquid  is  allowed  to  boil  for  a  short 
period  before  a  new  portion  of  the  carbonate  of  lime  is 
added.  The  liquid  can  hardly  be  obtained  entirely 
neutral ;  the  cessation  of  effervescence  must  therefore 

*  Some   manufacturers   apply  the   chalk  in   bags,  whereby  the 
settling  and  refining  are  simplified. 


THE   TECHNOLOGY    OF    STARCH-SUGAR.  205 

guide  the  neutralization.  The  point  when  neutraliza- 
tion ensues  is  best  approached  by  applying  at  the  final 
process  some  chalk-milk  wherein  the  carbonate  of  lime 
is  very  finely  divided.  For  this  ^purpose  powdered 
chalk  is  stirred  in  water  to  a  milk,  and  used  after  the 
coarser  parts  have  settled  to  the  bottom. 

Since  quicklime  can  be  slaked  in  water  to  a  very 
smooth  paste,  by  means  of  which  the  sulphuric  acid 
becomes  perfectly  neutralized,  without  ebullition,  the 
question  may  be  asked,  why  this  article  is  not  chosen 
if  only  for  the  purpose  of  avoiding  the  grinding  of  the 
chalk  or  limestone.  The  application  of  slaked  lime 
is  inadmissible  because  it  destroys  the  starch-sugar. 
It  is  impossible  to  add  the  lime-milk  to  acidy  sugar 
liquor  in  such  a  manner  that  neither  locally  nor  transi- 
torily too  large  an  amount  of  lime  comes  in  contact 
with  the  sugar.  Whenever  this  occurs  there  will  in- 
stantly be  produced  brownish  products  of  decomposi- 
tion of  the  sugar,  by  which  the  liquid  is  colored,  impart- 
ing to  it  a  bitter,  caramel-like  taste. 

The  neutralization  being  completed,  the  muddy  con- 
tents of  the  boiling-tub  are  left  to  run  into  a  depositing 
tank — a  wooden  tank— of  greater  height  than  width, 
which  is  supplied  with  cocks  or  spigots  for  drawing  off 
the  liquid.  In  the  larger  manufacturing  establishments 
there  is  to  be  found  adjacent  to  the  boiling  apparatus 
a  reservoir  placed  in  the  ground  and  lined  with  brick- 
work. Into  this  reservoir  the  contents  of  the  boiling 
apparatus  are  drawn,  and  afterwards  pumped  into  the 
depositing  vat.  If  several  boiling  tubs  or  converters 
for  boiling  with  steam  are  used,  they  may  be  used  at 
the  same  time  as  depositing  vats. 

After  the  lapse  of  from  twelve  to  twenty-four  hours 
the  gypsum  has  become  deposited,  so»that  the  saccha- 


206  MANUFACTURE   OF    STARCH,    ETC. 

rine  liquid  may  be  drawn  off.  The  sediment  or  the 
sugar  phlegm,  of  course  still  contains  a  considerable 
amount  of  saccharine  liquor.  For  the  recovery  of  this 
residuum  various  methods  have  been  recommended 
and  applied.* 

To  this  end  filtering-barrels  can  be  applied.  They 
consist  of  vertically  placed  barrels,  each  with  a  sieve 
bottom.  Above  the  sieve  bottom  a  piece  of  coarse  cloth 
is  spread;  upon  this  cut  straw  or  coarse  river  sand  is 
placed,  and  the  residuum  is  carefully  placed  thereon. 
The  liquid  will  then  run  out  by  the  stopcock — placed 
on  the  lower  bottom — pure  and  clear.  The  first  por- 
tion, coming  out  still  somewhat  muddy,  is  placed  back 
upon  the  filter.  Upon  the  residuum  gypsum  water  is 
carefully  poured,  after  the  upper  layer  has  been  made 
even,  and  is  somewhat  loosened.  Thereby  the  yet 
absorbed  sugar  liquor  is  dislodged ;  or  the  residue 
is  strained  through  bags  or  cloths,  the  press  cakes 
being  again  saturated  with  water,  and  the  pressing  is 
repeated. 

In  most  establishments,  the  removing  of  the  sugar 
liquor  from  the  sediment  is  frequently  accomplished 
by  the  use  of  the  bag-filter.  The  arrangement  of  these 
filters  is  delineated  in  Fig.  29.  They  consist  of  a  series 
of  long  and  small  bags  or  sacks,f  which  are  hung  up 
in  a  wooden  or,  better,  an  iron  closet-like  case,  with  a 

*  In  this  country,  in  order  to  accelerate  the  process,  the  bag-fil- 
ters are  of  a  very  large  capacit}'.  The  liquor  after  being  neutralized 
is  run  through  them  at  once,  thus  saving  the  time  absorbed  by  the 
use  of.  settling-tubs. 

f  Such  filter-bags  consist  of  (a)  the  inner  bags,  made  of  a  coarser 
material  than  the  outer  (6),  great  care  being  necessary  to  obtain 
for  these  latter  a  material  strong  enough  to  prevent  the  opening  of 
the  meshes,  by  the  great  weight  of  the  filtering  substance.  Strong 
unbleached  muslin  may  be  recommended  for  the  purpose. 


THE   TECHNOLOGY    OF    STARCH-SUGAR. 


207 


double  bottom.  The  space  on  the  top  forms  a  reservoir 
for  the  liquor  or  residuum  which  is  to  be  treated.  The 
lid  of  the  case  is  perforated  with  holes,  into  which  iron 
mouthpieces  of  the  shape  C,  or  simple  pieces  of  pipe 


Taylor's  bag-filter. 

are  inserted,  which  have  on  the  one  side  screw-threads 
and  on  the  other  little  collars,  upon  which  the  bags  or 
sacks  are  tied.  Generally  these  bags  are  double,  of 
cotton  and  linen,  the  inner  bags  much  wider,  and  con- 
sequently having  folds,  and  are  thus  better  adapted 
for  filtering,  while  inserted  in  the  outer  bag.  In  the 
lower  part  of  the  box  a  drain  pipe  is  inserted,  for 
drawing  off  the  clear  juice,  and  on  one  of  the  sides  is 
the  gate  &,  for  arranging  the  hanging  up  and  taking 
down  of  the  bags.  When  the  bags  containing  the 
deposit  are  so  filled,  that  no  more 'juice  runs  out,  they 


208 


MANUFACTURE    OF    STARCH,    ETC. 


are  taken  out  and  brought  under  a  screw-press,  where- 
by a  large  amount  of  the  liquor  still  retained  therein 
runs  out,  while  the  residuary  matter  remains  in  a  dense 
and  solid  form. 

Fig.  30. 


Johnson's  filter-press. 

Fig.  30  illustrates  a  filter-press  manufactured  by 
John  Johnson  &  Co.,  of  394  Oakland  Street,  Brooklyn, 
E.  D.,  New  York,  which  is  extensively  used  for  press- 
ing out  the  liquor  yet  held  in  the  paste-like  residuum 
found  in  the  bags,*  after  the  other  liquor  has  run 


THE    TECHNOLOGY    OF    STARCH-SUGAR.  209 

through  clear,  as  well  as  for  the  filtration  of  heavy 
glucose  or  grape-sugar  syrup,  to  separate  the  fine  par- 
ticles of  sulphate  of  lime  deposited  during  evaporation, 
which  are  held  in  mechanical  suspension  throughout, 
the  syrup  causing  a  cloudiness  or  dull  appearance, 
which  must  be  dispensed  with  to  complete  the  refining 
process. 

Johnson's  filter-press  consists  of  a  series  of  round 
or  square  plates,  usually  cast  iron,  having  projecting 
lugs  cast  on  each  side,  for  the  purpose  of  supporting 
them  in  a  press  frame  in  juxtaposition,  face  to  face, 
and  are  capable  of  being  screwed  up  tightly  between 
the  head  and  follower  of  the  press.  The  plates  are 
concave  on  each  side,  the  projecting  outer  rim  or 
edge  being  truly  surfaced  maintains  the  plate  surfaces 
at  distances  corresponding  to  the  depth  of  such  rims. 
The  plates  are  covered  with  suitable  filtering  cloth, 
and  the  method  which  the  Messrs.  Johnson  employ 
for  fixing  the  cloths  on  their  filter-press  is  decidedly 
the  simplest  and  most  effective  yet  introduced.  We 
will  give  a  brief  description,  which  will  enable  our 
readers  to  form  an  intelligent  idea. 

The  passage  of  inter-communication  by  which  the 
liquid  arrives  at  the  series  of  cells  being  formed  by  a 
simple  hole,  generally  through  the  centre  of  each  plate, 
a  pair  of  cloths  are  used  to  cover  each  side  of  a  plate, 
and  these  cloths  are  sewn  together  round  the  centre 
hole  corresponding  to  the  hole  in  the  plate.  It  is  ob- 
vious that  on  folding  one  cloth  and  passing  it  through 
the  hole  in  the  plate,  and  then  opening  it  out  on  the 
other  si'de  of  the  plate,  both  surfaces  will  be  suitably 
covered,  the  edges  of  the  cloth  passing  between  the 
surfaced  rims  of  the  consecutive  plates,  thus  improv- 
ing and  simplifying  the  means  of  clothing  the  filter- 

14 


'  •  -  •  lips 

210  MANUFACTUKE   OF    STAHCH,    ETC. 

press.  The  upper  part  of  the  cloth  is  held  in  position 
by  adjustable  tension  hooks,  which  provide  for  the 
shrinkage  or  slackness  of  the  cloth,  and  are  also  pro- 
vided with  ribs  or  channels  on  the  plate  surface  under 
the  cloth,  to  allow  the  filtrate  to  flow  away  to  the  out- 
let formed  in  the  bottom  of  the  filter  plate  at  the  back 
of  the  cloth.  The  spaces  between  the  cloth-lined 
plates  form  chambers  or  cells,  into  which  the  liquid  or 
semi-liquid  material  to  be  filtered  is  forced  under  pres- 
sure. A  passage  or  opening,  also  lined  with  cloth,  is 
formed  through  each  plate,  so  that  there  is  a  free  com- 
munication between  the  several  filtering  cells.  When 
the  liquid  or  semi-liquid  material  to  be  filtered  is 
forced  into  this  battery  of  cloth-lined  chambers  or 
cells,  the  liquid  is  forced  through  the  filtering  cloths 
which  cover  the  plates,  and  flows  away  to  the  outlet 
of  the  plate  by  following  the  channels  or  grooves  in 
the  plates,  which  have  free  communication  with  the 
outside  of  the  filter.  The  solid  matter,  sulphate  of 
lime,  etc.,  is  stopped  back  on  the  surface  of  the  cloth, 
and  by  a  continuance  of  the  operation  ultimately  fills 
the  cells,  and  can  be  removed  from  between  the  two 
cloth  covered  concave  plates,  forming  any  one  of  the 
chambers,  by  unscrewing  the  press  and  separating  the 
plates,  in  a  state  of  almost  perfect  dryness,  without 
removing  the  cloths. 

The  Process  of  Evaporation. — The  evaporation  of 
the  obtained  clear — or  at  least  tolerably  clear — sugar 
liquor  can  be  accomplished  either  over  a  direct  fire  or 
by  steam.  In  the  first  case  flat  pans  are,  used,  whose 
bottoms  are  only  touched  by  the  fire ;  in  the  other  case 
the  various  vacuum  pans  and  apparatus  serve  as  being 
best  suited  for  the  purpose  of  boiling  down  the  sugar 
liquor.  The  process  of  evaporating  cannot  be  finished 


THE    TECHNOLOGY    OF    STARCH-SUGAR.  211 

uninterruptedly,  since  the  solution  of  sugar  yet  contains 
dissolved  gypsum,  which  begins  to  separate  during  the 
evaporation,  and  by  leaving  the  liquid  stand  over  when 
it  has  evaporated  to  a  certain  point,  the  gypsum  is  sepa- 
rated as  completely  as  is  possible.*  The  evaporating, 
therefore,  although  at  first  it  may  take  place  by  lively 
boiling,  is  divided  into  two  periods:  the  evaporation 
to  the  degree  of  a  thin  syrupy  consistency,  and  the  eva- 
poration to  the  consistency  of  a  denser  syrup,  after  the 
removal  of  the  gypsum.  It  does  no  harm,  and  especi- 
ally not  in  the  manufacture  of  glucose,  to  add  sugar 
liquor  to  the  pan  in  the  same  ratio  as  the  contents  of 
the  pan  diminish  by  evaporation.  The  scum  produced 
during  the  process  of  evaporation  is  taken  off  with  a 
skimmer. 

As  soon  as  the  separation  of  the  gypsum  makes  it 
necessary,  or  when  otherwise  the  liquor  has  reached  a 
concentration  of  from  20°  to  30°  Baume  =  37°  to  57°  of 
the  saccharometer,  it  is  transferred  from  the  evaporat- 
ing-pans  into  upright  barrels,  provided  with  stopcocks 
or  spigots  for  depositing  and  separating  the  gypsum. 
When  finer  cloths  are  put  into  a  filter  press,  the  latter 
may  also  be  used  for  removing  the  separate  gypsum. 
If  this  has  been  accomplished,  after  the  lapse  of  several 
days,  then  the  clear  liquor  is  drawn  off  and  evaporated 
in  the  same  pans,  or  in  extra  pans,  to  a  dense  syrupy 
consistency,  i.  e.,  from  40°  to  45°  Baume.  In  larger 
manufactories,  vacuum-pans  are  used  for  this  purpose. 

*  I  have  found  that  a  liquor  evaporated  to  30°  B.,  and  left  to 
settle  for  a  long  time,  did  not  prevent  a  fresh  separation  of  g}'p- 
sum.  when  the  evaporation  afterwards  brought  the  liquor  to  a  higher 
density.  An  extra  chemical  treatment  is  necessary  to  eventually 
bring  forth  a  clear  and  transparent  syrup  — Hutter. 


212  MANUFACTURE    OF    STARCH,    ETC. 

The  deposits  of  gypsum  from  the  barrels  are  placed  in 
bag-filters,  and  after  draining  off  pressed. 

The  evaporation  of  the  sugar-liquor  in  open  pans 
does  not  allow  of  a  corresponding  utilization  of  the 
steam  or  fuel,  besides  which  the  liquor — while  exposed 
to  too  high  a  temperature — receives  a  dark  color,  and 
finally,  at  the  finishing  of  the  boiling  of  the  sugar- 
liquor,  a  strong  formation  of  scum  will  ensue. 

In  order  to  avert  these  troubles,  closed  evaporating 
apparatus  has  for  some  time  been  used.  Its  object  is, 
in  the  first  place,  the  evaporation  of  the  saccharine 
liquor  under  a  diminished  atmospheric  pressure.  By 
this  mechanism  it  becomes  possible,  to  apply,  in  place 
of  the  direct  steam  from  the  boiler,  that  which  has 
already  served  for  the  working  of  the  steam-engine 
(exhaust  steam).  The  temperature  of  this  steam  hav- 
ing decreased  correspondingly,  becomes  thus  better 
adapted  for  the  purpose.  Or  that  steam  is  utilized 
which  has  been  used  in  the  evaporation  of  the  liquor.* 

As  is  well  known,  liquids  will  come  to  a  boil  at  a 
considerably  lower  temperature,  by  diminution  of  the 
atmospheric  pressure.  The  rapidity  with  which  the 
water  evaporates  from  the  saccharine  liquor  in  the  first 
place  depends  on  the  difference  of  the  temperature  be- 
tween the  boiling  liquor  and  that  of  the  worm,  which 
latter  is  inserted  into  the  apparatus  for  increasing  the 
act  of  evaporation,  and  is  furthermore  dependent  on 
the  extent  of  the  heating  surface  of  the  worm.  "Inas- 
much, however,  as  the  saccharine  liquor  already  boils 
at  a  diminished  atmospheric  pressure,  i.  e.,  at  a  tempe- 

*  On  the  other  hand,  I  have  found  by  practical  experience  that 
such  exhaust  steam  will  never  do,  where  a  first-class  white  product 
is  required,  as  the  quality  of  the  article  depends  entirely  on  a  quick 
and  uninterrupted  evaporation. — Hutter. 


THE    TECHNOLOGY    OF    STARCH-SUGAR.  213 

rature  considerably  below  100°  C.  (212°  F.),  it  becomes 
possible  to  re-use  the  steam  that  has  already  served  for 
motive  power,  also  for  the  purposes  of  evaporation. 
This  return  or  exhaust  steam,  after  escaping  from  the 
cylinder  of  the  engine  without  pressure,  has  a  tempera- 
ture of  100°  C.  (212°  F.).  But  whenever  it  escapes 
by  a  counter-pressure  of  one-third  atmosphere,  its  tem- 
perature is  about  107°  C.  (224°.6  F.).  Such  steam 
will  serve  with  great  advantage  even  for  the  evapo- 
ration of  a  liquor,  which  boils  at  100°  C.  (212°  F.).  The 
difference  in  the  temperature  of  the  liquor  and  that  of 
the  steam  is  thus  far  certainly  not  considerable,  but  it 
can  be  increased  by  decreasing  the  boiling  point  of 
the  liquor,  and  by  diminution  of  the  atmospheric  pres- 
sure, for  instance,  to  94°  C.  (201°.2  F.). 

It  is  self-evident,  that  in  the  application  of  this 
improved  evaporating  apparatus,  care  must  be  ob- 
served, that  the  vapors  which  are  developed  from  the 
liquor  are  forced  out  by  the  vacuum-pump  as  fast  as  is 
possible.  To  this  end,  the  vapors  are  brought  into 
contact  with  cold  water,  by  means  of  a  second  vessel 
(the  condenser),  in  which  the  water  is  running,  and 
the  vapors  are  again  converted  into  water,  and  in  this 
state  removed.  The  water  has  a  volume  of  but  ^^th 
of  that  of  the  steam,  out  of  which  it  has  been  condensed. 
For  the  removal  of  the  condensation-water,  an  accu- 
rately constructed  and  powerfully  acting  suction- 
pump,  as  is  illustrated  by  Fig.  31,  serves,  and  which 
also  simultaneously  supplies  the  vacuum  in  the  evapo- 
rating apparatus.  Inasmuch  as  with  the  juice,  and 
especially  with  the  absorbing  water,  air  will  constantly 
enter  into  the  apparatus  again,  this  must  needs  be  re- 
moved, if  the  requisite  vacuum  is  to  be  maintained. 
The  task  of  the  pump— to  force  out  both  air  and  water — 


214  MANUFACTURE    OF    STARCH,    ETC. 

Fig.  31. 


"Wet  air-pump. 


THE    TECHNOLOGY  OF    STARCH- SUGAR.  215 


mm* 


216  MANUFACTURE    OF    STARCH,    ETC. 

never  ceases.  This  service  does  not  cease  even  then, 
when  the  process  of  evaporation  in  the  apparatus  is  in 
full  activity.  For  this  reason  this  pump  is  called  the 
" wet  air-pump" 

We  also  present  in  Fig.  32  one  of  Guild  &  Garri- 
son's pumps,  which  may  be  used  as  wet  or  dry  pumps, 
working  equally  well  under  any  circumstances,  and 
are  an  independent  vacuum-pump  of  the  highest  effi- 
ciency. 

By  the  sketches,  Figs.  33  and  34,  are  represented 
the  longitudinal  section  and  the  upper  part  of  a  vacuum 
apparatus. 

A  is  the  boiling  vessel  (the  vacuum),  mostly  of 
a  more  or  less  spherical  shape.  Upon  this  is  placed 
the  cylindrical  ajutage,  (?,  the  dome,  which  is  to  pre- 
vent the  boiling  over  of  the  liquor.  From  the  upper 
part  of  the  dome  the  pipe  m  conducts  the  vapors  into 
the  "overflow,"  from  whence  they  enter  into  the  con- 
denser, p. 

The  liquids  enter  into  the  vacuum  A  through  the 
so-called  feeding  pipe,  which  is  closed  by  means  of  the 
"  suction  cock."  For  the  purpose  of  admitting  the 
various  liquors  and  syrups  which  are  to  be  evaporated, 
as  well  as  the  water  (for  cleaning  the  vacuum  pan) 
from  the  respective  tanks,  usually  four  u  suction  pipes" 
(not  visible  in  the  sketch)  serve. 

The  heating  of  the  liquor  is  accomplished  by  means 
of  direct  steam,  which  is  conducted  through  the  valve 
(shown  in  Fig.  33)  from  the  steam  boiler  into  the 
steam  port  «7.  The  steam  enters  either  into  the  worm 
a  a,  Fig.  33,  or  into  the  steam  jacket  of  the  vacuum 
pail.  For  the  draining  off  of  the  condensed  water  and 
the  uncondensed  steam  from  the  worm  as  well  as  from 


THE   TECHNOLOGY    OF    STARCH-SUGAR. 

Fig.  33. 


217 


Vacuum  apparatus. 
(Longitudinal  section.) 

Fig.  34. 


1  Meter. 


Vacuum  apparatus. 
(Upper  view.) 

the  double  bottom,  special  "  reversible  cocks,"  K  (Fig. 
3±)  serve.  For  the  admission  of  air  and  an  easy 
outlet  of  steam  from  the  double  bottom  of  the  va- 


218  MANUFACTURE    OF    STARCH,    ETC. 

cuum  pan,  in  order  to  effect  a  quick  moderation  of  the 
temperature,  an  air-cock  serves. 

To  the  vacuum  pan  are  attached  a  thermometer  and 
a  vacuum  gauge.  The  apparatus  is  also  supplied 
with  a  stopcock,  J^and  G  (Fig.  34),  for  the  admission 
of  air  or  fat  (paraffine).  In  the  upper  part  of  the 
vacuum  pan  are  placed  two  eye-glasses  for  the  purpose 
of  observing  the  boiling1  of  the  liquor  A  (Fig.  31). 
These  eye-glasses  are  lighted  by  a  lamp  or  a  gas  flame. 

Another  important  piece  of  mechanism  on  the  va- 
cuum pan  is  the  so-called  proof-stick,  by  means  of 
which  a  sample  of  the  boiling  juice  can  be  taken  out 
at  any  time  for  the  purpose  of  examining  the  state  of 
concentration  without  admitting  any  air.  The  vacuum 
pan  is  closed  air-tight  by  a  conical  pin  d  (Fig.  33). 
This  conical  pin  is  affixed  below,  and  is  of  cast  iron 
covered  with  India  rubber.  It  is  pressed  against  the 
apex  by  the  lever  c.  For  cleaning  the  apparatus  the 
manhole  B  (Fig.  34)  serves. 

The  vapors  enter,  as  already  stated,  by  the  pipe  m 
(Fig.  33)  in  the  overflow  and  condenser  p,  where  the 
injecting  mechanism  (the  rose)  is  placed. 

The  letters  on  Fig.  34  designate  the  following  im- 
portant parts  of  the  vacuum  pan,  some  of  which  do 
not  at  all  appear  in  the  drawing:  A.,  eye-glass  with 
lamp;  B,  manhole;  (7,  conical  stopper;  D,  trial  gauge; 
E,  eye-glass;  F  and  Gr,  valves  for  admitting  air;  // 
and  /,  valves  for  admitting  steam  ;  K,  exhaust  valve ; 
Jj,  waste-cock;  M,  cock  for  injecting  water ;  JV,  valve 
of  the  air-pump;  0,  lever  for  the  conical  pin.* 

*  Mr.  G.  F.  Ott,  207  Buttonwood  Street,  Philadelphia,  is  making 
a  specialty  of  vacuum  pans  of  copper,  wrought  and  cast  iron,  well 
adapted  for  evaporating  sugar  liquor,  and  of  great  merit. 


THE    TECHNOLOGY    OF    STARCH-SUGAR.  219 

Instead  of  vacuum  pumps,  more  recently  steam-jet 
condensing  machines  are  frequently  used  (Fig.  35). 
This  apparatus  acts  by  means  of  a  passing  jet  of  water 
and  by  a  fine  stream  of  fresh  steam.  The  outer  casing 


Vacuum  steam-jet  condenser, 

of  the  apparatus  consists  of  cast  iron,  the  inner  parts  cf 
brass.  The  condenser  is  erected  vertically.  At  a  is  the 
entrance  for  the  water;  the  water  is  admitted  by  a  pres- 
sure of  about  5  metres  (16.4  feet).  If  a  proper  height  for 
the  fall  is  wanting,  the  water  is  either  conducted  from 
a  correspondingly  high  reservoir,  or  by  a  pump  of  a  like 
force.  In  case  pumps  are  used  in  a  direct  way,  an  air- 
chamber  must  be  inserted  in  the  conduit  of  water  in 
order  always  to  have  uniform  pressure.  At  5,  a  jet  of 
fresh  steam  is  admitted  by  means  of  a  hollow  needle, 
which  bv  its  swiftness  increases  the  effect  of  the  water 


220  MANUFACTURE    OF    STARCH,    ETC. 

forced  through  the  jet.  As  is  evident,  the  steam  be- 
comes by  its  contact  with  the  water  condensed.  At  c, 
the  evaporating- pipe,  which  issues  from  the  vacuum- 
pan,  is  connected.  The  vacuum  attainable  by  this  me- 
chanism borders  on  the  absolute ;  of  course  under  the 
condition  that  all  parts  of  the  apparatus  are  fitted  air- 
tight. This  apparatus  requires  for  each  1  weight  part 
evaporating  vapors  30  weight  parts  of  water  for  con- 
densing, and  one-tenth  weight  part  of  fresh  steam,  or 
thus  expressed,  1  litre  (2.1  pints)  of  water  to  be  evapo- 
rated requires  30  litres  (7.9  galls.)  of  condensing  water 
and  0.10  kilogramme  (0.22  Ib.)  of  steam.  The  impel- 
ling power  of  the  steam-jet  condenser  begins  by  open- 
ing, in  the  first  place,  the  water  conduit,  thereupon 
admitting  the  fresh  steam,  and  then  conducting  the 
evaporating  fumes  to  it.  The  turning  off  is  accom- 
plished in  reversed  order. 

The  "steam-jet  condensers"  are  made  of  various 
sizes,  and  of  any  desired  capacity. 

Inasmuch  as  a  nice  brown  color  is  much  desired  for 
glucose-syrup,  if  it  is  intended  to  serve  as  a  substitute 
for  the  syrups  of  the  East  or  West  Indies,  or  as  an 
admixture  with  the  latter,  a  discoloration  by  means  of 
boneblack  is  not  always  demanded. 

If  the  syrup  is  not  to  be  discolored,  it  is  boiled  down  in 
the  vacuum-pan  to  40°  or  42°  Baume,  weighed  at  60°  to 
65°  C.  (140°  to  149°  F.),  and  thereupon  again  forced 
through  the  filter-press.  For  this  operation  the  first 
filter-press  may  be  used,  after  a  previous  cleaning  of 
the  same ;  but  it  is  better  to  set  up  a  second  press  for 
this  purpose,  which  may  be  of  smaller  dimensions.  Of 
course  the  syrup,  while  passing  through  the  filtering- 
press,  must  be  kept  at  a  correspondingly  high  tempe- 


THE    TECHNOLOGY    OF    STARCH-SUGAR.  221 

ratnre  (75°  C.,  167°  F.).  The  filtering-cloth  for  this 
operation  is  of  a  lighter  quality. 

But  if,  notwithstanding,  the  saccharine  liquor  is  as 
usual  passed  through  filters  of  coarsely  powdered 
animal  charcoal  (as  is  done  in  beet-  and  cane-sugar 
manufactories),  or  if  the  refining  is  carried  out  with 
fine  charcoal  and  blood,  this  is  also  done  for  the  pur- 
pose of  producing  the  syrup  absolutely  discolored  like 
water,  and  to  refine  its  taste. 

Thefilteringthroughboneblack  is  accomplished  most 
rationally  at  a  degree  of  concentration  of  32°  Baume, 
weighed  at  60°  to  65°  C.  (140°  to  149°  F.)  of  the  liquor. 
This  is  to  be  done,  after  the  gypsum  has  deposited  itself 
from  the  evaporated  liquid,  by  means  of  a  prolonged 
rest.  The  liquor  must,  however,  previously^be  heated 
again.  If  starch-syrup  or  glucose  is  for  an  extended 
time  kept  at  a  temperature  near  its  boiling  point,  it 
assumes  a  darker  color,  becomes  sweeter,  and  loses 
more  and  more  the  tendency  to  crystallize. 

For  the  manufacture  of  the  solid  starch-sugar  but 
little  need  be  added  to  the  preceding.  Whether  the 
starch-syrup  thus  obtained  remains  liquid,  or  in  time 
congeals  into  solid,  grainy,  starch-sugar,  depends,  not 
so  much  on  its  concentration,  as  on  the  quality  of  the 
same.  If  the  operation  has  been  so  manipulated  that 
in  the  syrup,  besides  sugar,  a  certain  quantity  of  starch- 
gum  (dextrine)  is  still  present,  the  syrup  will  remain 
liquid,  even  at  a  very  considerably  high  degree  (45°  B.) 
of  concentration.  If  the  aim  has  been  most  complete!}7 
to  transform  the  starch  into  sugar,  i.  e.,  if  sulphuric 
acid  has  been  applied  in  larger  quantity,  and  the  boil- 
ing continued  for  a  longer  period  of  time,  a  syrup  will 
result,  which  already  by  an  inferior  concentration  will 
in  time  separate  grainy  sugar,  and  by  increased  con- 


222  MANUFACTURE   OF    STARCH,    ETC. 

centration  will  gradually  entirely  congeal  to  a  grainy 
sugar.  Such  syrup  is  permitted  to  stand  in  moderately 
warm  rooms,  in  wooden  vessels  or  in  earthen  basins, 
until  it  congeals.  For  producing  a  solid,  white  sugar, 
the  treatment  of  the  saccharine  liquor  with  boneblack 
for  the  purpose  of  discoloring  is  indispensable. 

The  liquid  syrup  or  glucose  is  generally  packed  in 
strong  casks  or  tuns  of  soft  wood,  and  is  even,  despite 
the  greatest  care,  exposed  to  the  danger  of  a  large  de- 
gree of  shrinkage.  During  hot  weather  its  transporta- 
tion is  almost  impossible,  since  the  syrup  absorbs  the 
water  contained  in  the  wood,  and  in  consequence 
thereof  the  casks  become  dry,  and  the  syrup  leaks  out. 
In  case  the  boiling  process  has  not  been  properly  at- 
tended to,  the  article  will  easily  ferment  and  spoil. 

These  great  obstacles  and  difficulties  of  the  syrup 
traffic  and  transport  are  overcome  by  introducing  this 
article  to  commerce,  at  present,  principally  in  a  coagu- 
lated, more  solid  form,  that  of  crude  or  refined  grape- 
sugar.  The  syrup  boiled  down  to  a  corresponding 
concentration  can  by  means  of  a  simple  mechanical 
manipulation  easily  and  quickly  be  turned  to  a  perfect 
congelation  or  coagulation.  Already  in  1865  the  pecu- 
liarity of  the  starch-syrup  was  known  under  certain  con- 
ditions to  coagulate  in  a  spontaneous  way;  as,  for  in- 
stance, after  having  been  for  a  longer  time  deposited  in 
warehouses,  or  whenever  it  is  heavily  jolted  for  a  longer 
period  during  its  transportation.  Upon  this  peculiar 
property  of  the  starch-syrup  rests  the  mechanical  mani- 
pulation whereby  it  is  caused  to  become  stiff.  If  the 
starch-syrup  has  finished  boiling  it  is,  after  cooling  off, 
diligently  stirred  or  beaten.  Thus  treated  it  will  coagu- 
late or  congelate  within  eight  or  ten  hours  so  perfectly 


THE    TECHNOLOGY    OF    STARCH-SUGAR.  223 

as  to  assume  a  soaplike  consistency,  without,  of  course, 
altering  its  quality.  In  this  condition  it  can  be  far 
better  preserved  and  more  easily  transported.  It  can 
in  this' state  be  cast  into  suitable  forms,  and'  may  be 
transported  in  very  light  cases  made  of  thin  and  soft 
wood,  and  can  also  be  handled  much  better  and  more 
satisfactorily. 

In  the  present  state  of  the  development  of  the  glu- 
cose-syrup and  sugar  manufacture,  both  the  coagula- 
tion of  the  glucose  and  the  longer  period  of  the  sugar 
remaining  liquid  are  considered  as  faults,  and  justly 
so.  From  this  it  becomes  clear  that  the  liquid  glucose 
having  the  property  of  coagulating  very  quickly  can- 
not be  adapted  to  form  an  article  of  the  syrup  trade, 
because  neither  manufacturers  nor  consumers  will  de- 
signate it  any  longer  as  syrup,  or  treat  it  as  such;  but 
from  the  time  of  its  coagulation  it  will  hence  pass  only 
as  grape-sugar. 

The  products  of  starch-syrup  and  the  starch-sugar 
manufacture  may  thus  be  classified  : — 

a.  Starch-syrup,*  an  article  which  for  a  compara- 
tively long  time  remains  clear  and  liquid. 

ft.  Common  starch-sugar,  obtained  by  congelation  of 
starch-syrup,  and  being  characterized  by  containing  a 
relatively  large  amount  of  dextrine. 

c.  Purified  or  refined  starch-sugar,  obtained  by  a  re- 
peated refining  of  the  common  starch-sugar. 

d.  Granulated  starch-sugar  obtained  by  congelation, 
but  containing   the  smallest   possible    percentage   of 
dextrine. 

If  the  product  is  to  be  disposed  of  as  solid  sugar, 
and  not  as  syrup,  the  liquor  is  evaporated  in  flat  eva- 

*  The  commercial  term  for  this  is  glucose. 


224  MANUFACTURE    OF    STARCH,    ETC. 

porating  vessels,  to  from  40°  to  42°  B.,  and  then  placed 
in  crystallizing  pans.  After  the  crystallization  has 
commenced  the  sticky  liquid  is  filled  into  small  barrels 
wherein  the  mass  after  a  short  time  entirely  coagulates, 
and  can  thus  be  shipped.  The  mass  may  also  be 
allowed  to  become  solid  in  the  pans,  and  then  be 
ground  and  packed.  Some  manufacturers  produce  a 
dry  and  grainy  sugar.  The  sugar-formation  from 
starch  in  this  case  is  manipulated  in  the  same  manner 
as  stated  above.  It  is  of  importance  that  the  trans- 
formation hereby  of  the  starch  into  sugar  ensues  as 
completely  as  possible,  since  the  presence  of  greater 
quantities  of  the  remaining  dextrine  will  hinder  the 
granulation. 

Starch-syrup  in  the  liquid  state,  or  glucose,  and  the 
crude  or  common  grape-sugar  are,  as  regards  their 
quality  and  price,  simply  one  and  the  same  product, 
however  much  they  may  differ  in  external  appearance. 
Both  these  articles,  the  starch-syrup  and  the  starch- 
sugar,  still  contain  much  unchanged  dextrine  or  gum. 
This  article  is  thrown  out  from  the  refined  granulated 
grape-sugar,  and  is  known  as  molasses.  We  have  al- 
ready stated  that  the  complete  transformation  of  the 
dextrine  in  the  starch-syrup  can  only  be  accomplished 
at  the  expense  of  the  quality  of  the  product,  since  by 
the  too  long-continued  boiling  products  of  decomposi- 
tion will  be  created,  possessing  a  disagreeable,  bitterish 
taste,  and  thus  causing  the  syrup,  or  the  common  grape- 
sugar,  to  become  unfit  for  consumption  and  valueless. 
A  total  transformation  of  the  dextrine  into  sugar  has 
proved,  for  the  reasons  stated,  as  entirely  impracticable. 
The  common  grape-sugar  is  therefore,  as  regards  its 
chemical  ingredients  as  well  also  as  the  action  of  these 
ingredients  on  each  other,  entirely  identical  with  the 


THE   TECHNOLOGY    OF    STARCH-SUGAR.  225 

liquid  glucose.  But  in  general  the  composition  of  the 
common  starch-sugar,  or  that  of  the  glucose,  is  so  varied 
that  scarcely  two  samples  of  the  article  can  be  found 
which  possess  an  equal  percentage  of  the  composition 
of  their  ingredients,  as  may  be  seen  from  the  subjoined 
analyses : — 


Liquid  starch-syrup 
or  glucose. 

Common 

starch-sugar  (stocked 
starch-sugar). 

Water        .... 

I. 

21.8 
42.2 

II. 
20.8 
56.0 

22.6 
0.6 

III. 

27.8 
56.2 

15.6 
0.4 

IV. 
27.4 

58.8 

13.3 
0.5 

V. 
26.0 
61.5 

12.0 
0.5 

Dextrine  and  intermediate  ; 
products 
Mineral  ingredients  . 

|  35.4 
0.6 

100.0          100.0  100.0          100.0          100.0 

From  these  analyses  of  the  liquid  starch-syrup  and 
the  common  grape-sugar,  as  obtained  from  different 
sources,  it  can  be  seen  that  both  these  products  are  in 
fact  mixtures  composed  of  water,  dextrine,  mineral 
substances,  etc.,  with  a  quantity  of  starch-sugar  vary- 
ing from  42  to  65  per  cent.  It  will  be  perceived  that 
they  will  form,  neither  in  a  liquid  nor  in  a  solid  condi- 
tion, a  pure  starch-sugar,  and  that  especially  the  starch- 
syrup  in  solid  form,  bearing  erroneously  in  commerce 
the  name  "starch-sugar,"  is  yet  far  from  being  solid, 
pure  starch-sugar. 

SPECIAL  DIRECTIONS  FOR  THE  MANUFACTURE  OF 
STARCH-SUGAR. 

Pay  en's  Method  for  the  Manufacture  of  Starch-syrup 
and  Sugar. — According  to  the  directions  of  Payen  the 
boiling,  or  the  conversion  of  the  starch  into  sugar,  is  to 
be  performed  in  large  and  very  thick  vats  or  tubs  of 
wood  A  A  (see  the  illustration  Fig.  36).  Each  of  these 
vats  has  a  capacity  of  125  hectolitres  (350  bushels); 

15 


226 


MANUFACTURE    OF    STARCH,    ETC. 


their  staves  have  a  thickness  of  about  10  to  12  centi- 
metres (3.9  to  4.7  inches).  A  lead  pipe  ~b  c  d  runs  into 
the  vat  A  to  the  bottom  ccZ,  the  part  cdis  there  on  the 


THE    TECHNOLOGY    OF    STARCH- SUGAR.  227 

bottom  bent  into  a  circle,  and  at  short  distances  slits 
are  made  in  the  pipes  by  a  saw. 

The  vat  is  filled  to  about  one-third  of  its  capacity 
with  sulphuric  acid  water,  and  then  the  liquid  is  heated 
by  steam.  This  is  done  by  admitting  the  steam  from 
the  boiler  i  through  the  copper  pipe  g  e  e  b  (which  near 
b  can  be  stopped  off  by  the  stopcock  "A")  and  by  the 
leaden  pipe  bed  the  steam  enters  the  vat.  During 
the  boiling  the  vat  is  covered,  and  the  vapors  drawn 
off  are  immediately  conducted  into  a  chimney,  or  they 
pass  through  a  main  pipe  into  the  horizontally  placed 
worm  E  F,  to  be  utilized  for  the  process  of  evapora- 
tion. This  drawing  off  of  the  vapors  becomes  neces- 
sary on  account  of  the  bad  odors  which  are  developed 
by  the  heating  of  the  starch  with  acid,  and  originates 
from  the  oily  contents  of  the  starch.*  If  these  vapors 
escape  at  once  through  the  chimney  the  stench  will 
become  quite  troublesome  to  the  neighborhood,  while 
by  the  cooling  off  in  the  pipe  the  volatile  oil  becomes 
in  a  great  measure  condensed  with  the  steam,  and  thus 
collects  between  the  pipes  ^and  G  in  the  vessels  which 
are  placed  below  it.  In  this  way  the  non-condensed 
parts  escape  through  the  pipe  F'  F"  along  with  the 
vapors,  and  as  they  are  thus  weaker,  and  there  is  less 
of  them,  they  become  net  so  noticeable.  In  order  en- 
tirely to  destroy  these  vapors  they  may  be  conducted 
into  the  fireplace  under  the  boiler  instead  of  passing 
through  the  chimney. 

In  the  present  case  we  pour  into  the  vat  (boiling- 
coop)  about  3000  kilogrammes  (6600  l.bs.)  of  water, 
mixed  with  one-half  of  the  sulphuric  acid  necessary  for 

*  Potato-starch  has  more  of  these  oily  contents  than  corn-starch. 


228  MANUFACTURE   OF    STARCH,    ETC. 

the  transformation    of  the   starch.     The  water   thus 
acidified  is  heated  to  100°  C.  (212°  F.). 

Meantime  the  quantity  of  3000  kg.  (G600  Ibs.)  of  the 
commercial  dry  starch  is  placed  in  a  vat  of  correspond- 
ing size,  and  set  above  the  boiling-coop.  In  this  other 
vat  the  other  half  of  the  requisite  sulphuric  acid  (in 
the  present  instance  from  30  to  60  kg.)  (66  to  132  Ibs.) 
and  a  corresponding  quantity  of  water  have  previously 
been  poured  in  order  to  produce  the  starch-milk.  This 
starch-milk  is  admitted  into  the  boiling-coop  by  a  cock 
which  is  situated  in  the  bottom  of  the  upper  vat,  and 
should  run  in  a  uniform  stream  through  the  funnel  a 
into  the  boiling  vat,  commonly  called  the  converter. 
The  smaller  the  quantity  of  water,  in  comparison  to  the 
amount  of  starch  to  be  converted,  the  more  care  must 
be  taken  during  the  admission  of  the  starch-milk  into 
the  boiling-coop,  so  that  the  boiling  of  the  liquid  is  not 
interrupted  even  for  a  moment,  so  as  to  avoid  the  for- 
mation of  a  paste,  a  serious  matter  during  the  course 
of  the  formation  of  sugar.  By  the  gradual  admission 
of  the  starch-milk  the  temperature  of  the  mass  increases 
constantly,  so  that  it  finally  reaches  that  of  the  boiling- 
point  of  an  equally  concentrated  sugar  solution. 

If,  finally,  all  the  starch-milk  has  passed  into  the 
boiling  sulphuric  acid  water — requiring  from  one  to 
one  and  a  half  hour's  time — the  boiling  is  yet  continued 
from  two  and  a  half  to  three  hours,  in  case  of  the  pro- 
duction of  glucose,  but  in  the  case  of  sugar  the  period 
is  from  four  to  six  hours.  A  longer  boiling  furnishes  a 
colored  article  of  a  bitterish  taste,  without  attaining  a 
perfect  sugar  formation.  The  progress  of  the  trans- 
formation is  noticed  by  the  iodine  and  alcohol  test. 

When  the  transformation  is  finished  the  free  sul- 
phuric acid  is  removed  from  the  liquor.  This  is  accom- 


THE    TECHNOLOGY    OF    STARCH-SUGAR.  229 

pi i shed  by  stirring  finely-powdered  chalk  or  limestone 
(carbonate  of  lime)  in  small  portions  into  the  heated 
liquor  until  ebullition  no  longer  ensues.  The  car- 
bonate of  lime  neutralizes  the  acid,  since  while  the 
carbonic  acid  gas  escapes-,  indissoluble  sulphate  of  lime 
(gypsum)  is  formed.  For  each  1  kg.  (2.20  Ibs.)  of 
acid  a  little  more  than  1  kg.  of  chalk  is  required. 
When  the  liquid  is  neutral  it  will  not  redden  blue  lit- 
mus paper,  or  at  least  but  very  faintly. 

After  saturation  the  liquor  is  allowed  to  settle  for 
twelve  hours.  This  can  be  done  either  in  the  coop 
itself,  or  in  the  reservoir  (tank)  A"  which  is  placed 
thereunder,  in  case  a  new  quantity  of  starch  is  to  be  at 
once  transformed  into  sugar.  Thereupon  the  clear 
liquor  is  drawn  off  and  heated  to  60°  C.  (140°  F.),  and 
refined  through  the  filter  H  H  by  animal  charcoal. 
The  gypsum  residue  is  placed  by  itself  over  a  linen 
filter,  and  after  dripping  off  washed  out. 

The  saccharine  liquor  or  thin  juice  filtered  through 
the  boneblack  being  15°  to  16°  B.  is  collected  in  the 
lower  reservoir  L  L,  from  whence  it  is  raised  by  a 
pump  into  the  upper  reservoir  M ;  from  thence  it  flows 
off  into  the  horizontal  channel  m,  which  is  supplied 
with  a  number  of  slits,  and  from  this  it  runs  down 
through  the  side  slits  over  the  heated  worm-shaped 
evaporator  E F.  Underneath  this  apparatus  the  syrup 
collects  in  a  gutter^?,  and  now  flows  through  the  pipe 
y  into  the  reservoir  r,  where  it  is  finally  drawn  off  ac- 
cording to  requirement,  by  means  of  the  pipe  s  and 
the  spigots  n  n,  thence  to  run  into  the  evaporating  pan 
P  Pr.  Over  these  pans  is  a  casing  of  wood  in  order 
to  conduct  the  steam  into  a  chimney.  The  syrup  is 
evaporated  in  these  vessels  to  30°  B.,  whereby  again 
some  gypsum  becomes  separated,  which  must  be  re- 


230  MANUFACTURE   OF    STAKCH,    ETC. 

moved  from  the  liquid  by  a  prolonged  depositing  of 
the  same. 

The  starch-syrup  thus  obtained  is  already  service- 
able for  distillers  and  beer  brewers,  etc.  For  many  other 
applications,  however,  as  for  baking,  for  cordials,  etc., 
it  must,  after  twenty-four  hours,  be  again  heated  to 
60°  C.  (140°  F.),  and  filtered  through  coarse  animal 
charcoal,  whereupon  the  filtered  syrup  is  immediately 
packed  up  in  barrels. 

This  room- and  time-wasting,  troublesome,  uncleanly, 
and  loss-entailing  older  method,  finds  at  present  appli- 
cation in  but  few  establishments. 

Maubr&s  Method  for  the  Manufacture  of  Starch-syrup 
and  Sugar. — As  may  be  seen  from  the  preceding  the 
starch-gum,  or  dextrine,  which  besides  starch-sugar  is 
formed  by  the  action  of  the  sulphuric  acid  upon  the  starch 
must,  by  a  continued  boiling  with  the  acid,  be  trans- 
formed as  completely  as  is  possible  into  sugar.  This 
transformation,  however,  ensues  by  applying  ordinary 
pressure  but  very  slowly.  For  this  reason  most  of  the 
manufacturers  who  operate  according  to  the  old  method, 
do  not  wait  for  the  complete  transformation,  but  rather 
prefer  to  furnish  a  sugar  for  the  trade  which  holds  a 
large  amount  of  dextrine.  The  conversion  of  starch 
into  glucose  and  sugar  succeeds,  however,  all  the  faster 
when  the  boiling  of  the  starch  takes  place  under  a 
higher  pressure  than  the  common  atmospheric,  or  what 
amounts  to  the  same,  when  the  action  of  the  acid  upon 
the  starch  ensues  under  an  increased  temperature. 
Upon  this  fact  rests  MaubrPs  method  of  manufacturing 
glucose,  patented  in  England  in  1864. 

The  mixture  of  starch  with  diluted  sulphuric  acid  is 
boiled  at  a  high  pressure,  and  at  a  temperature  of  160°C. 
(320°  F.).  By  this  treatment  the  action  of  the  sul- 


THE   TECHNOLOGY    OF    STABCH-SUGAR.  231 

phuric  acid  upon  the  starch  is  increased,  the  transfor- 
mation of  the  dextrine  into  sugar  is  attained  more 
perfectly,  and,  moreover,  the  forming  volatile  oils, 
which  impart  a  disagreeable  taste  to  the  glucose,  are 
distilled  off  and  destroyed. 

To  attain  this  end  a  steam-boiler,  in  the  shape  of  a 
high-pressure  boiler,  is  most  suitable.  It  is  to  be  con- 
structed of  strong  iron  plates,  so  as  to  withstand  a 
pressure  of  45  kilogrammes  (99  Ibs.)  per  square  inch 
(6  atmospheres);  inside  it  is  lined  with  lead,  and  out- 
side is  covered  with  a  double  casing.  The  interme- 
diate space  between  the  boiler  and  the  casing  is  about 
10  centimetres  (3.9  inches)  wide,  and  filled  with  a  sub- 
stance being  a  non-conductor  of  heat  (sand,  etc.).  In 
the  boiler  A  A  (Fig.  57)  is  placed  a  perforated  leaden 


Maubre's  apparatus  for  the  manufacture  of  glucose. 

pipe  o  o  o  for  conducting  the  steam  therein.  For  fill- 
ing up  the  boiler  with  the  starch-milk  the  conduit  pipe 
6?,  which  is  supplied  with  a  stopcock,  serves;  besides 
this  the  boiler  is  supplied  with  safety  valves  D  Z>,  the 
test-cock  H,  and  the  thermometer/;  C C are  the  man- 
holes ;  E  is  the  receiving  pipe  for  the  products  of  dis- 


232  MANUFACTURE    OF    STARCH,    ETC. 

tillation  (the  volatile  and  empyreumatic  oils) ;  F  the 
pipe  for  the  steam  ;  t/is  the  gauge  showing  the  amount 
of  liquor;  L  the  pipe  for  admitting  the  steam  ;  M the 
outlet-cock;  jY~a  pipe  for  admitting  water. 

The  substances  are  prepared  for  the  boiler  in  the 
proportions  as  follows  : — 

28  kilgr.  (61.60  Ibs.  of  sulphuric  acid  of  60°  B.  are 
diluted  in  2800  kilgr.  (6160  Ibs.)  of  water.  While  this 
mixture  is  heated  in  the  boiler  to  100°  C.  (212°  F.)  a 
further  quantity  of  28  kg.  (61.60  Ibs.)  of  sulphuric  acid 
is  diluted  in  2800  kg.  (6160  Ibs.)  of  water  in  an  open 
wooden  tank,  which  is  supplied  with  a  stirring  appara- 
tus. This  mixture  is  heated  by  steam  to  30°  C.  (86°  F.). 
In  this  latter  liquid  1120  kilogrammes  (2464  Ibs.)  of 
starch  are  placed  well  stirred  in  and  heated  to  38°  C. 
(100.4°  F.)  The  starch-milk  thus  obtained  is  then 
gradually  poured  into  the  boiling  diluted  sulphuric 
acid  of  the  boiler  by  means  of  the  pipe  '(?,  and  the  en- 
suing mixture  is  kept  at  a  boil.  As  soon  as  all  the 
starch  is  in  the  boiler  the  cock  of  the  conduit-pipe  is 
closed  and  steam  is  now  admitted,  until  a  temperature 
of  160°  C.  (320°  F.)  and  a  pressure  of  6  atmospheres 
are  attained.  Thereupon  the  cocks  E  and  F  on  the 
outlet  pipes  are  opened  for  the  outlet  of  the  steam,  as 
also  for  the  removal  of  the  products  of  distillation, 
while  the  temperature  of  the  liquid  is  maintained  by 
means  of  steam  (from  the  pipe  o  o  o)  at  160°  C.  (320°  F.). 
Thus  ensues  an  almost  complete  transformation  of  gum 
into  sugar,  as  well  as  the  perfect  volatilization  of  the 
oils  formed.  The-temperature  of  160°  C.  (320°  F.)  is 
kept  up  so  long,  until  samples  taken  out  by  means  of 
the  cock  P,  will  indicate  that  the  starch  or  the  dextrine 
has  been  transformed  into  sugar.  This  is  accomplished 


THE   TECHNOLOGY   OF    STARCH-SUGAR.  233 

according  to  the  grade  of  the  purity  of  the  starch  ap- 
plied, in  a  period  of  from  two  to  four  hours.* 

The  test  whether  the  starch  or  the  dextrine  has  be- 
come transformed  into  sugar  is  determined  by  the  re- 
action of  iodine  upon  it,  and  by  means  of  acetate  of 
lead.  The  iodine  reaction  tends  to  prove  that  all  the 
starch  has  become  changed,  while  the  acetate  of  lead 
will  indicate  the  almost  complete  disappearance  of  the 
dextrine.  Of  course  the  sample  taken  out  of  the  boiler 
must  be  previously  neutralized,  then  filtered  through  a 
small  charcoal  filter,  and  only  thus  applied.  After  ceas- 
ing to  form  sugar  the  sweet  liquor  is  to  be  drawn  off  for 
the  purpose  of  neutralization  of  the  sulphuric  acid.  It 
is  drawn  into  an  open  wooden  vessel  which  is  supplied 
with  a  stirring  apparatus  and  waste-cock.  There- 
upon 84  kilogrammes  (184.8  Ibs.)  of  purified  carbonate 
of  lime  are  stirred  into  250  kilogrammes  (550  Ibs.)  of 
water,  and  gradually  added  to  the  liquor.  The  sulphate 
of  lime  thus  formed  is  allowed  to  deposit,  which  re- 
quires a  period  of  from  two  to  four  hours.  Finally, 
the  neutral  saccharine  solution  is  filtered  through  bag 
filters,  and  evaporated  to  35-°  B.,  cleared  with  blood 
and  boneblack,  again  filtered  through  bags  and  bone- 
black  filters,  and  then  crystallized. 

The  sugar  thus  manufactured  is  entirely  pure  and 
free  from  any  bitter  or  empyreumatic  taste. 

Landmanrfs  Method  of  Manufacturing  Starch  Syrup 
and  Sugar. — Landmann  applies  to  100  kilogrammes 
(220  Ibs.)  of  carefully  washed  potato-starch  from  350 
to  400  kilogrammes  (770  to  880  Ibs.)  of  water  and  10 
kilogrammes  (22  Ibs.)  of  concentrated  sulphuric  acid 
(an  enormous  quantity).  The  acid  is  added  to  the 

*  Mostly  in  a  great  deal  less  time. — Hutter. 


234  MANUFACTURE   OF    STARCH,    ETC. 

water,  the  mixture  kept  at  a  boil,  and  the  starch 
milk  is  added  in  small  portions,  and  thereupon  boiled 
so  long  that  a  solution  of  iodide  of  potassium  (to 
which  a  little  muriatic  acid  or  nitric  acid  has  been 
added)  no  longer  produces  a  blue  or  a  brownish-red 
color.  Landmann  considers  this  juncture  the  point 
when  the  formation  of  sugar  is  completed  to  such 
a  degree  that  all  the  dextrine  has  become  trans- 
formed into  sugar.  (This  opinion  must  however  be 
regarded  as  erroneous.)  The  sulphuric  acid  is  neutral- 
ized with  lime;  the  liquid,  freed  of  gypsum,  is  treated 
with  three  parts  of  refined  animal  charcoal,  and  there- 
upon evaporated  to  the  consistency  of  syrup. 

Landmann's  process,  however,  is  never  applied,  and 
possesses  merely  an  historical  interest. 

Rossling  and  ReichardVs  Apparatus  for  the  Manufac- 
ture of  Glucose. — Rossling  and  Reichardt  have  con- 
structed an  apparatus  for  the  manufacture  of  glucose 
and  grape-sugar,  which  is  still  of  interest  at  this  time, 
on  account  of  its  successful  application  in  producing 
glucose  on  a  smaller  scale. 

The  construction  of  this  apparatus  in  a  vertical  sec- 
tion, is  delineated  in  Fig.  38.  $  is  the  furnace  opening, 
F  the  fireplace,  R  the  grate,  a?,  y  and  w,  z  the  mechan- 
ism for  the  support  of  the  barrel,  consisting  of  a  ring- 
plate  and  pipe,  a?,  w  are  screws  for  the  air-tight 
fastening  of  the  barrel.  A  the  ashpit,  f,f  apertures 
with  pipes  and  cocks,  op  q  r  the  neck  of  the  boiler. 

P  represents  the  barrel  of  white  pine- wood,  with  a 
bottom  of  at  least  2.5  to  3  centimetres  (0.985  to  1.18 
inch)  thick.  JD,  H  a  tube  made  of  linden  or  maple- 
wood,  5  centimetres  (1.97)  inch  thick  and  2  centi- 
metres (0.787)  inch  wide,  abed  is  a  pipe  with  four 
steam  outlets  below,  two  of  which  are  visible  at  c  and  d. 


THE   TECHNOLOGY   OF    STARCH-SUGAR.  235 

The  surface  of  the  liquid  in  the  steam-vats  must 
compare  to  that  in  the  boiler  as  6  to  5.     In  the  repre- 

Fig.  38. 


Rossling  and  Reickardt's  apparatus. 

sentation  (Fig.  38),  the  dimensions  are  taken  in  such 
a  way  that  20  kilogrammes  (44  Ibs.)  of  starch  can  be 
operated  upon  at  once. 


236  MANUFACTURE    OF    STARCH,    ETC. 

Aniliorfs  Method  of  Manufacturing  Grape-sugar. — 
The  most  excellent  grape-sugar  is  furnished  by  the 
method  invented  by  E.  F.  Anthon,  and  his  process  of 
manufacture,  as  well  as  his  mechanical  appliances,  have 
been  patented  in  many  countries.  Anthon,  who  is  the 
founder  of  this  important  branch  of  industry  in  Austria, 
has  organized  several  large  concerns,  which  work  ac- 
cording te  his  method,  and  with  the  best  success,  a 
proof  of  the  excellence  thereof. 

The  manipulation  itself — according  to  the  inventor's 
own  description — is  as  follows  : — 

The  Boiling  of  1200  kilogrammes  (2640  Ibs.)  of  dry 
starch  and  2000  kilogrammes  (4400  Ibs.)  of  green  starch. 
— 1.  Boiling.  1200  kilogrammes  (2640  Ibs.)  of  dry  starch 
are  stirred  up  in  1400  kilogrammes  (1.4  cubic  metres  = 
14  hectolitres  =  370  galls.)  of  water  to  a  homogeneous 
milk,  and  thereupon  run  into  the  converter  in  a  uniform 
stream.  The  converter  must  previously  be  charged 
with  a  mixture  of  200  kilogrammes  (=  2  hectolitres  = 
52.8  galls.)  of  water  with  48  Ibs.  of  oil  of  vitriol,  and 
brought  to  the  boiling-point.  The  steam  jet  and  the 
streaming  in  of  the  milk  should  be  so  regulated  that 
the  mass  continues  to  boil  uninterruptedly.  In  order 
to  attain  this  end  during  the  winter  season,  the  starch 
may  be  stirred  with  tepid  water,  but  not  so  warm  that 
the  starch  becomes  pasty.  The  adding  of  the  starch 
is  to  be  so  regulated,  that  within  the  course  of  one 
hour  the  entire  starch-milk  has  been  emptied  into  the 
boiling  vessel.  Stirring  is  unnecessary,  but  the  steam 
is  regulated  so  that  the  mass  steadily  boils.  The 
starch-milk  in  the  stirring  tank  must  be  kept  con- 
stantly in  motion,  to  avoid  a  settling  of  the  same  upon 
the  bottom.  When  the  mixture  has  been  kept  at  a 
boil  for  about  one  hour,  after  the  entire  mass  has  been 


THE    TECHNOLOGY    OF    STARCH-SUGAR.  237 

emptied  into  the  boiling  vat,  the  boiling  is  continued 
from  four  to  five  hours  longer.  This  length  of  time  is 
required  for  making  the  hard  crystallized  sugar,  but 
when  syrup  is  intended,  or  better,  when  the  final  aim 
is  to  obtain  glucose,  a  three  hours' boiling  is  sufficient. 
But  the  boiling  is  now  kept  up  but  gently,  and  for  this 
purpose  a  small  amount  of  steam  is  sufficient. 

2.  Neutralization.  After  the  mixture  has  been  kept 
at  a  boil  from  five  and  a- half  to  six  hours  (from  the 
time  of  the  pouring  in  of  the  starch-milk),  the  process 
of  neutralizing  commences;  for  this  purpose  30  kilo- 
grammes (66  Ibs.)  of  good  boneblack,  and  25  to  30 
kilogrammes  (55  to  66  Ibs.)  of  purified  chalk  are  used. 
The  chalk  must  previously  be  mixed  in  water  and 
strained  through  a  fine  sieve. 

At  first,  10  kilogrammes  (22  Ibs.)  of  boneblack  are 
gradually  thrown  into  the  boiling  mass,  and  then  the 
chalk-milk  is  poured  in  through  a  leaden  pipe,  which 
reaches  down  to  the  lower  half  of  the  boiling  vat.  But 
great  care  must  be  taken  that  the  seething  liquid  does 
not  flow  over  the  rim  of  the  boiling  vessel. 

Having  added  a  sufficient  amount  of  chalk  so  that 
the  mixture  reacts  but  moderately  sour,  and  hence  lit- 
mus paper  will  be  colored  merely  a  slight  violet,  the 
adding  of  chalk  is  interrupted,  and  the  balance  of 
20  kg.  (44  Ibs.)  of  boneblack  is  now  added.  The 
quantity  of  boneblack  can  be  increased  or  decreased 
according  to  need.  But  it  should  be  made  a  rule  that 
one-third  of  the  boneblack  is  to  be  added  before  throw- 
ing in  the  chalk,  and  two-thirds  afterwards. 

After  finishing  the  process  of  neutralization  the  mix- 
ture is  allowed  to  boil  gently  for  about  ten  minutes, 
and  is  then  passed  through  a  Taylor  filter  of  linen  bags. 
All  having  run  out  of  the  converter  it  is  then  washed 


238  MANUFACTURE    OF    STARCH,    ETC. 

out  with  some  water,  and  this  also  left  to  run  into  the 
bags.  When  nearly  all  liquor  has  run  through  them, 
and  the  substance  remaining  in  them  is  a  thick  paste, 
then  it  is  carefully  edulcorated  with  water  until  the 
liquor  drained  off  indicates  but  from  2°  to  4°  B.  The 
first  part  of  the  liquor  running  off  has  to  be  almost 
colorless  and  clear,  and  while  yet  warm  indicate  about 
16°  B. 

3.  Evaporation.  The  thin  liquor  is  evaporated  at 
once.  In  case  common  coagulated  sugar  is  to  be  pro- 
duced, it  is  to  be  condensed  to  33°  or  36°  B.  (weighed 
while  hot);  but  if  hard  crystallized  sugar  is  aimed  at 
it  must  weigh  about  33°  B.  (weighed 'hot).  The  syrup 
obtained  by  the  former  method  is  then  passed  through 
a  small  Taylor  filter  of  flannel  bags.  The  syrup  thus 
obtained  is  now  left  to  cool  off.  This  is  performed 
either  in  small  coolers,  or  in  small  woo.den  tanks  lined 
with  zinc  or  copper. 

After  cooling  off,  a  few  kilogrammes  (kg  =  2.2  Ibs.) 
of  half-congealed  sugar  of  a  former  boiling  are  added 
and  thoroughly  stirred  in.  After  the  lapse  of  from  ten 
to  twenty  hours  the  mass  will  have  become  so  stiff 
that  (for  the  production  of  common  sugar)  it  can  be 
put  into  barrels,  boxes,  etc.,  and  left  therein  to  com- 
pletely harden.  The  more  of  the  granulated  sugar 
that  has  been  stirred  in,  and  the  syrup  been  beaten, 
the  more  uniform  the  sugar  coagulates. 

o  O 

111  the  production  of  hard-crystallizing  sugar,  the 
effort  should  not  be  to  cause  a  quick  congelation,  but 
on  the  Qontrary,  the  endeavor  should  be  to  keep  the 
mass  soft.  To  this  end  the  evaporation  is  stopped  at 
33°  B.,  the  stirring  should  not  be  so  strong,  and  not  so 
repeatedly  conducted,  when  the  partly  coagulated 
sugar  is  being  added.  Whenever  in  this  latter  case 


THE    TECHNOLOGY    OF    STARCH-SUGAR.  239 

the  body  of  the  sugar  has  attained  a  completely  stiff 
consistency,  so  that  it  can  only  be  scooped  out  with 
difficulty,  it  is  then  to  be  subjected  to — 

4.  Pressure.  For  this  operation  cloths  of  coarse, 
solid  gray  linen  and  ordinary  iron  pressing-plates  of  47 
to  53  centimetres  (18.5  to  20.9  inches)  square  are  ap- 
plied. The  placing  in  of  the  paste  is  performed  by  first 
laying  a  wooden  frame  upon  the  plate.  This  frame  is 
to  be  4  centimetres  (1.57  inches)  high,  and  measuring 
from  44  to  49  centimetres  (17.3  to  19.3  inches)  in  the 
clear.  A  press-cloth  is  then  folded  crosswise,  and 
spread  over  it,  and  the  sugar-paste  put  thereon.  The 
paste  is  spread  uniformly,  and  the  folds  of  the  cloth 
are  joined  together,  the  frame  is  lifted  off,  another 
plate  placed  upon  it,  etc.,  until  the  space  in  the  press 
is  filled  up. 

The  press  is  then  very  gradually  drawn  together  so 
as  to  avoid  the  tearing  of  the  cloths.  When  finally, 
after  the  tightest  pressing,  no  more  syrup  flows  off, 
then  the  pressing  is  considered  as  ended.  For  this 
operation  hydraulic  presses  or  powerful  screw  presses 
are  used.  At  all  events,  the  presses  should  be  so  con- 
structed that  the  frame  be  as  high  as  possible  (1.75 
metres  =  5.74  feet)  so  that  a  giving  away  of  the  in- 
serted'mass  becomes  impossible.  It  is  best  to  press 
twice,  first  in  a  less  powerful  press,  and  thereupon  after 
the  readjusting  of  the  plates,  in  a  very  powerful  second 
press.  The  press-cakes,  when  taken  out  of  the  cloths 
after  such  a  treatment,  are  composed  of  such  pure 
sugar  that  the  same  may  be  used  at  once  for  the  pur- 
pose of  improving  wines  and  cordials,  and  especially 
.  for  confectionery,  etc. 

The  most  practical  way  of  getting  rid  of  the  syrup 
is  to  use  the  centrifugal  machine.  Half  the  labor  is 


2J:0  MANUFACTURE    OF    STARCH,    ETC. 

thus  only  required,  and  a  better  result  obtained  in  less 
time. 

Of  all  the  different  kinds  of  such  machines  now  in 
use  we  have  found  those  made  by  H.  "W.  Lafferty, 
Gloucester,  Jf.  J.,  the  best  suited  for  the  purpose.  The 
following  figure  (39)  gives  a  view  of  a  vertical  section 

Fig.  39. 


H.  W.  Lafferty's  centrifugal  machine. 
(Vertical  section.) 


of  their  apparatus,  showing  the  construction  of  the 
same,  while  the  next  figure  (40)  shows  a  set  of  four  of 
their  centrifugals.  With  a  speed  of  from  800  to  900 


THE   TECHNOLOGY   OF   STARCH-SUGAR. 


241 


16 


242  MANUFACTUKE    OF    STARCH,    ETC. 

revolutions  per  minute  such  a  machine  will  do  as  much 
work  in  a  given  time  as  any  other  machine,  effect  a 
saving  of  power,  and  reduce  the  wear  and  tear  and 
danger  consequent  upon  higher  speed.  In  discharging 
the  dry  sugar  from  this  machine  it  is  only  necessary 
to  raise  a  valve  in  the  centre  of  the  basket,  and  cut  the 
sugar  from  the  sides.  It  then  falls  through  an  opening 
into  a  receptacle  below  and  at  the  back  of  the  machine. 
Another  improvement  is  the  brake  for  stopping,  which 
is  operated  by  the  same  lever  that  is  used  for  starting, 
by  raising  or  lowering  the  basket.  Any  floor  of  a 
factory  possessing  the  stability  to  cany  the  weight  of 
the  machine  will  answer  for  the  purpose  of  a  bed,  no 
shaking  or  jarring  being  noticed  during  the  rotation  of 
the  basket.  This  house  also  manufactures  the  raw  and 
refined  starch  centrifugals  now  so  much  preferred  to 
the  use  of  the  inclined  plane — bringing  forth  six  square 
cakes  which  are  very  dry,  and  may  at  once  be  brought 
into  the  drying-rooms  for  the  finish.  All  those  ac- 
quainted with  the  slow  process  of  the  inclined  plane 
and  the  so-called  finishing  troughs,  will  find  them  a 
great  and  meritorious  improvement. 

If  it  should  be  desired  to  make  leaf-sugar,  then  the 
following  manipulation  must  be  observed  : — 

5.  Remelting.  The  press-cakes  or  sugar  taken  from 
the  centrifugal  basket  are  broken  up  into  small  pieces 
and  melted,  but  without  adding  any  water.  This  is 
done  in  a  kettle  which  is  more  flat  than  deep,  and 
not  over  an  open  fire,  but  over  a  steam-bath.  The 
melting  is  aided  by  an  occasional  gentle  stirring  in  a 
temperature  as  low  as  is  possible.  The  heating  is  con- 
tinued until  all  lumps  have  become  crumbled  up,  but- 
Hot  until  the  fine  parts  are  dissolved.  For  400  kilo- 
grammes (b80  Ibs.)  of  sugar  this  melting  operation 


THE  TECHNOLOGY  OF  STARCH-SUGAR.     243 

requires  from  three  to  four  hours'  time.  A  complete 
dissolving  of  the  sugar  must  be  at  all  times  avoided, 
since  those  parts  of  sugar  which  finally  float  in  the 
solution,  are  the  means  of  the  ensuing  of  a  nice  crystal- 
lization. When  the  sugar  thereupon  has  passed  into  the 
solution,  in  the  manner  set  forth,  the  temperature  at  this 
juncture  being  about  70°  to  80°  C.  (158°  to  176°  F.), 
the  mass,  having  attained  the  proper  consistency,  is 
then  cast  into  the  moulds.  After  two  days'  rest  the 
sugar  is  entirely  solid,  and  is  removed  from  the  moulds. 

6.  Utilization  of  the  pressed-out  Syrup.     Of  100  kilo- 
grammes (220  Ibs.)  of  dry  starch,  57  klgr.  (125.4  Ibs.) 
press-cake  are  obtained,  and  about  50  klgr.  (110  Ibs.) 
of  press-syrup.     This  syrup  can  either  be  mixed  with 
such  syrup  as  contains  a  large  amount  of  dextrine,  and 
sold  as  such,  or  boiled  and  worked  over  again  so  as  to 
make  a  second  product  of  press-cakes.     To  this  end  it 
is  evaporated  to  from  36°  to  37°  B.  (weighed  while  hot), 
permitting  it  to  cool  off  and  to  coagulate  as  described 
heretofore;  whereupon  it  is  likewise  pressed  out.  The 
press-cakes  thus   obtained   furnish   a   less  handsome 
article,  and  it  is  best  to  dispose  of  the  press-syrups  as 
such. 

7.  By  the  aid  of  Sulphurous  Acid.     In   order  to 
obtain  a  product  of  tne  whitest  possible  color,  the 
application  of  sulphurous  acid   has  been  frequently 
mentioned.     This  acid  is  manipulated  thus:  after  half 
of  the  requisite  quantity  of   chalk  has  been  applied 
during  the  process  of  neutralization,  the  further  add- 
ing of  chalk  is  interrupted,  and  placing  into  the  boil- 
ing vat  either  1.5  or  2  kilogrammes  (3.3  or  4.4  Ibs.)  of 
dry,  or  5  kilogrammes  (11  Ibs.)  of  liquid  sulphite  of 
lime ;   continuing   the   boiling   for   ten    minutes,  and 
thereupon  adding  the  rest  of  the  chalk.     In  conclu- 


244  MANUFACTURE    OP    STARCH,    ETC. 

sion,  it  may  be  remarked,  that  it  is  imperative  to  carry 
out  the  process  with  great  cleanliness,  and  to  use  no 
other  water  but  such  as  contains  no  hygroscopic 
ingredients,  and  none  which  will  be  turned  brown  by 
sulphuric  acid. 

The*  sugar  obtained  by  this  process  is  hard  and 
white  like  loaf  sugar,  and  porous,  but  of  course  does 
not  possess  the  transparent  crystalline  appearance,  but 
looks  dull  and  whitish.  It  contains  95.3  per  cent,  of 
anhydrous  starch-sugar  and  4.7  per  cent,  of  water. 
Its  contents  of  water,  therefore,  do  not  exceed  two 
equivalents  (10  per  cent.),  as  is  the  case  with  common 
hard  starch-sugar,  but  only  one  equivalent  (5  per 
cent.).  It  corresponds  to  the  formula,  Ci2Hi2Oio-fHO, 
while  the  common  starch-sugar  corresponds  to  C12Hi2 
O12+2HO. 

ANTHON'S  LATEST  IMPROVEMENTS  FOR  THE  MANU- 
FACTURE OF  SMALLER  QUANTITIES.  HlS  PER- 
FECTED MACHINERY. 

I.  The  Method  of  producing  from  160  to  200  Mo- 
grammes  (352  to  440  Ibs.)  of  Glucose,  within  twenty -four 
hours. — Proportion  of  the  material  to  be  mixed  for  a 
boiling : — 

168  kilogrammes  (370  Ibs.)  of  air-drj-  starch. 

5  "  (  11    "  )  of  sulphuric  acid  of  66°  B. 

1.68        "  (3.70  "  )  of  bone-black. 

1.12  to  1.68        "  (2.46  to  3.70  Ibs.)  of  pure  burned  lime. 

2.25        "  (4.95  Ibs.)  of  prepared  chalk. 

II.  Fitting  up  of  the  Apparatus. — The  machinery 
which  Anthon  applies  for  this  method  is  very  simple, 
and  is  represented  in  Fig.  41 ;  a  is  the  pan,  6  a  vat 
of  about  3  hectolitres   (8.4  bushels)  capacity  with  a 


THE    TECHNOLOGY    OF    STARCH-SUGAR. 


245 


wooden  spigot  g  affixed  at  the  bottom;  c  Taylor's 
bag-filter  placed  in  a  closet-like  case.  This  case  is 
1.25  metres  (4.1  feet)  high  and  64  centimetres  (25.2 
inches)  wide,  and  deep  (square).  It  is  arranged  for 
the  reception  of  nine  bags,  each  of  about  80  centi- 
metres (2.6  feet)  in  length,  and  of  15  to  18  centimetres 
(5.9  to  7  inches)  diameter,  when  it  is  filled.  This 
filter-closet  must  be  set  up  in  such  a  manner  that  the 
thin  liquor  can  be  drawn  oif  by  a  small  gutter,  not 
only  into  the  tank/,  but  also  directly  into  the  pan  d. 


Fig.  41. 


DecimiO 


1  Meter. 


Anthon's  perfected  machinery  for  the  manufacture  of  grape-sugar  on  a 

small  scale. 

The  bags  for  this  filter  are  to  be  made  of  gray  linen 
of  a  prime  quality  and  of  uniform  weft.  These  bags 
must  be  fastened  over  the  funnels  eee,  with  strong  cord. 


246  MANUFACTURE    OF    STARCH,    ETC. 

/.  Barrel  of  about  3  to  3.5  hectolitres  (8.4  to  9.8  bus.) 
capacity,  for  receiving  the  filtered  thin  juice.  A  very 
small  Taylor  filter  is  furthermore  required.  The  same 
should  also  be  encased  with  wood,  and  contain  a  space 
for  but  six  bags,  of  56  centimetres  (1.83  feet)  length, 
and  from  13  to  15  centimetres  (5.1  to  5.9  inches)  in 
diameter  (when  filled  up). 

The  entire  height  of  this  closet  is  to  be  8  centime- 
tres (3.15  inches),  its  depth  37  centimetres  (1.2  feet), 
and  its  width  53  centimetres  (1.74  feet).  The  filter 
contains  double  bags  ;  the  outer  of  coarse  gray  linen, 
serving  for  the  purpose  of  supporting  the  inserted 
flannel  bags.  The  latter  must  be  made  somewhat 
larger,  than  those  of  linen,  because  the  flannel  shrinks 
by  exposure  to  the  heat,  and  these  flannel  bags  should, 
even  after  having  shrunk,  be  still  somewhat  larger 
than  those  made  of  linen.  Finally  a  wooden  tank  for 
the  finished  sugar  is  required.  This  tank  should  be 
lined  throughout  with  very  thin  copper  sheets. 

III.  Manipulation. — At  six  o'clock  in  the  morning 
168  kilogrammes  (369.6  Ibs.)  of  water  (measured)  are 
placed  in  the  previously  scoured  pan  a,  and  from  168 
to  196  kilogrammes  (369.6  to  431.2  Ibs.)  of  water  in 
the  vat  5.  A  fire  is  kindled  under  the  pan,  and  while 
constantly  stirring  168  kilogrammes  (369.6  Ibs.)  of 
starch  are  put  in  the  vat  &.  Before  this,  while  yet  the 
water  in  the  pan  a  is  cold,  1.68  kilogrammes  (3.69  Ibs.) 
of  sulphuric  acid  are  slowly  and  cautiously  added, 
while  stirring.  The  acid  however,  may  previously  be 
diluted  in  3.36  kilogrammes  (7.39  Ibs.)  of  water.  This 
is  done  in  a  vessel  lined  with  thin  lead;  and  it  can 
then  be  poured  in  at  once. 

If  a  heated  room  is  adjacent,  it  would  be  well,  espe- 
cially in  winter,  to  allow  the  starch  to  stand  for  a  few 


THE   TECHNOLOGY    OF    STARCH-SUGAR.  247 

days,  in  order  to  warm  it  through.  It  is  also  best,  if 
the  water  which  is  to  be  poured  into  the  starch-stirring 
vats,  has  a  temperature  of  50°  C.  (122°  F.).  When 
the  acid-water  in  a  is  at  a  full  boil,  and  the  starch  in  b 
is  uniformly  stirred  up,  then  the  latter  is  permitted  to 
flow  through  the  cock  g  in  a  small  jet  towards  a. 
During  this  operation,  the  stirring  must  notecase,  and 
the  liquid  must  be  kept  at  a  constant  boil ;  and  paste 
formation  is  to  be  carefully  avoided.  When  all  the 
starch-milk  has  run  into  the  pan  (this  should  be  accom- 
complished  by  8  A.  M  ),  the  further  stirring  may  be 
stopped,  and  the  mixture  must  be  allowed  to  keep  on 
gently  boiling. 

This  boiling  is  to  be  continued  from  five  to  seven 
hours,*  or  at  least  so  long  until  a  little  sample  of 
the  liquor,  into  which  some  alcohol  is  dropped,  will 
no  longer  produce  a  milky  and  turbid  sediment.  The 
evaporating  water  is  to  be  replaced  by  fresh  water 
during  the  process.  If  the  liquid  should  be  condensed 
by  this  process  to  above  20°  B.,  then  the  evaporated 
water  should  be  renewed  by  a  fresh  supply,  or  what  is 
still  better,  by  adding  some  of  the  drained-oif  water  of 
a  former  boiling.  As  soon  as  the  alcoholic  test  no 
longer  shows  a  milky  sediment,  the  fire  is  gradually  di- 
minished, and  now  the  process  of  neutralization  begins. 
To  this  end.  2.25  kilogrammes  (4.95  Ibs.)  of  lime  have 
been  slaked  on  the  preceding  day,  and  being  mixed 
into  a  milky  substance,  and  strained  through  a  small, 
narrow  wire  sieve,  are  thus  in  a  fine  jet  poured  into 
the  pan,  while  a  rapid  stirring  is  maintained.  There- 
upon a  mixture  of  1.68  kilogrammes  (3.7  Ibs.)  of  pre- 
pared chalk  in  3.36  kilogrammes  (7.39  Ibs.)  of  water 

*  When  glucose  is  to  be  the  final  resuU,  only  three  hours. 


248  MANUFACTURE    OF    STARCH,    ETC. 

(which  has  also  previously  passed  through  a  wire 
sieve)  are  added,  until  no  more  effervescence  occurs, 
and  a  piece  of  blue  litmus  paper  is  yet  colored  red, 
whereupon  finally  1.68  kilogrammes  (3.7  Ibs.)  of  bone- 
black  dust  are  stirred  in.  Thereupon  the  entire  con- 
tents of  the  pan  are  brought  into  the  somewhat  moist 
bags  of  the  filter,  but  the  cooling  off  of  the  liquid  must 
always  be  avoided  in  this  operation,  as  much  as  is  pos- 
sible. The  first  part  of  the  drained  off  substance  being 
somewhat  turbid  or  dull  is  always  returned  to  the 
filter.  The  substance  should  be  equally  distributed  in 
all  the  bags,  as  this  will  tend  materially  to  lessen  the 
work  of  the  process  of  edulcoration.  The  pan  being 
empty,  is  washed  out  with  pure  water,  and  this  water 
added  to  the  liquor  in  the  filter,  and  then  the  substance 
in  the  bags  is  completely  edulcorated  by  applying 
pure,  fresh  water.  As  soon  as  the  liquor  issues  much 
weaker  (about  10°  B.)  it  is  no  longer  allowed  to  run 
towards  f,  but  it  is  collected  in  various  portions  (ac- 
cording as  its  density  decreases)  to  be  added  to  the 
mixture  of  a  subsequent  boiling. 

The  emptying  and  washing  out  of  the  pan  should  be 
hastened,  in  order  at  once  to  place  the  yet  heated  and 
filtered  thin  liquor  in  the  same,  and  to  evaporate  it 
quickly,  by  keeping  up  a  brisk  fire.  At  this  juncture 
the  thin  liquor  of  the  filter  is  no  longer  permitted  to 
flow  towards  f,  but  to  run  directly  into  the  pan,  as 
long  as  the  liquor  indicates  more  than  from  10°  to  12° 
B.,  whereupon  it  is,  as  already  mentioned,  to  be  col- 
lected in  portions.  As  soon  as  all  the  thin  liquor 
is  in  the  pan,  the  boiling  is  continued,  until  it  indi- 
cates a  density  of  32°  to  35°  B.  (weighed  while  hot), 
the  fire  is  then  removed,  the  syrup  placed  on  the 


THE   TECHNOLOGY    OP    STARCH-SUGAR.  249 

flannel  filters,  and  it  can  be  used  at  once,  after  cool- 
ing off. 

The  drawing  off  from  the  pan  must  be  attended  to 
with  great  care,  so  that  it  be  cooled  off,  as  well  as  the 
brickwork,  so  that  by  the  time  of  its  nearly  complete 
emptying,  the  remainder  of  the  sugar  solution  will  not 
begin  to  burn.  As  soon  as  the  glucose  solution  is  fil- 
tered off  from  the  flannel  bags,  the  pan  is  washed  out 
with  some  thin  liquor  and  water,  and  this  liquid  is 
poured  into  the  filter-bags,  and  these  latter  are  allowed 
to  hang  overnight  undisturbed.  On  the  following 
day  the  contents  of  these  bags  are  emptied  into  the 
pan,  after  another  conversion  has  been  made  and  fin- 
ished after  the  neutralizing  of  this  second  boiling. 

The  connecting  channel  from  the  fireplace  of  the  pan 
to  the  chimney  is  to  be  established  in  the  shortest  pos- 
sible way,  and  in  a  straight  line.  A  door  for  cleaning 
purposes  should  be  likewise  attached. 

In  the  left  corner  of  the  pan,  an  elbow-pipe,  about 
15  centimetres  (5.9  inches)  in  width,  and  supplied  with 
a  damper,  is  inserted,  whereby  a  direct  connection  is 
maintained  between  the  actual  fireplace  and  the  chim- 
ney, in  order  to  avoid  the  driving  back  of  the  smoke, 
while  the  fire  is  being  kindled. 

The  pan  must  always  be  kept  clean  and  well  scoured, 
and  should  be  covered  with  a  lid  of  wood,  in  which  an 
opening  of  from  14  to  16  centimetres  (5.5  to  6.3 
inches)  square  is  made;  at  all  events  it  should  be 
large  enough  to  allow  the  insertion  of  a  light  wooden 
chimney,  which  extends  above  the  roof  of  the  establish- 
ment for  the  escape  of  the  steam. 

The  Production  of  Capillair  Syrup  and  Sugar. — 
Some  few  establishments  have  furnished  quite  recently 
an  absolutely  water-clear  syrup,  which  in  a  very  con- 


250  MANUFACTURE    OF    STARCH,    ETC. 

densed  state  is  known  in  the  market  by  the  designa- 
tion of  capi  Hair-syrup.* 

The  modus  operandi  for  producing  this  brilliant 
glucose  is  as  follows: — 

After  the  starch  has  been  boiled  in  the  usual  man- 
ner for  procuring  a  syrupy  article,  and  after  the  pro- 
cess of  neutralization  is  finished,  the  clear,  thin  liquor 
of  from  16°  to  20°  B.  thus  obtained  is  condensed  in  a 
vacuum  pan  to  30°  B.  (weighed  while  boiling  hot). 
The  vacuum  pan  should  be  of  copper,  because  by  this 
process  of  evaporating  the  liquor  the  gypsum  will  de- 
posit itself  on  the  copper  pipes  as  firmly  as  stone,  and 
hence  the  pipes,  by  aid  of  muriatic  acid,  have  to  be 
frequently  cleaned. 

If  the  temperature  in  the  vacuum  can  be  maintained 
at  57°.5  to  63.75°  C.  (135.5°  to  146.75°  F.)  the  syrup 
will  remain  so  much  the  lighter.  The  time  occupied 
by  the  process  of  evaporation  also  influences  the  color 
of  the  article.  The  more  rapidly  the  evaporation  en- 
sues the  lighter  the  syrup  will  be.  This  syrup  has  not 
to  be  clarified  by  settling,  and  this  method  is  yet  main- 
tained in  some  manufactories.  But  inasmuch  as  the 
settling  of  the  liquor  occupies  a  long  time,  and  since 
the  gypsum  never  completely  separates  from  this 
already  somewhat  heavy  syrup,  the  filter-presses  are 
used  for  this  operation  to  great  advantage.  Thus  the 
clarifying  process  is  much  accelerated,  and  the  thin 
syrup  issues  from  the  filter  presses  free  from  gypsum, 
and  entirely  clear. 

From  the  filter  press  the  syrup  is  directly  pumped 
into  the  reservoir,  and  from  thence  to  the  borieblack 
filter. 

*  This  glucose  is  the  article  used  so  extensively  by  the  confec- 
tioners and  others  in  the  United  States. — Hutter. 


THE   TECHNOLOGY    OF    STARCH-SUGAR.  251 

These  filters  are  to  be  from  3  to  3.5  metres  (9.8  to 
11.5  feet)  high,  and  of  a  diameter  of  .75  metre  (2.5  feet). 
The  syrup  must  pass  slowly  through  the  filters,  and 
the  first  part  of  the  filtered  liquor,  being  of  yellowish 
and  muddy  color,  is  again  placed  in  the  reservoir,  from 
whence  it  is  again  pumped  on  to  the  filter. 

The  filtered  liquor  is  now  sucked  into  the  vacuum 
pan,  and  evaporated  at  a  temperature  of  from  56.5° 
to  62.5°  C.  (133.7°  to  144.5°  F.).  If  the  syrup  is  to  be 
used  for  exportation  the  condensation  is  to  be  =  44°  B. 
(weighed  at  61°  to  62.5°  C.  =  141.8°  to  144.5°  F.).  The 
process  of  evaporation  goes  on  very  quickly,  since  the 
syrup  already  possesses  a  consistency  of  from  28°  to 
30°  B.  before  it  enters  the  vacuum,  so  that  from  10  to 
15  kilogrammes  (22  to  33  Ibs.)  of  syrup  can  be  finished 
within  one  and  a  half  hours.* 

The  capillair-syrup  for  the  export  trade  has  to  be 
filled  into  the  casks  while  yet  lukewarm.  If  it  cools 
off  entirely  it  will  not  run  out  of  the  vats  at  all,  or  so 
sluggishly  that  it  would  occupy  a  great  deal  of  time. 

The  perfectly  white  and  finest  quality  of  grape- 
sugar,  which  also  passes  through  theboneblack  filters, 
is  known  as  capillair  grape-sugar ,  and  is  manipulated 
in  a  similar  way  to  that  for  the  production  of  syrup, 
with  this  difference,  viz.,  that  the  syrup  at  the  last 
stage  is  condensed  from  44°  to  45°  B.,  while  for  the 
production  of  sugar,  the  process  of  evaporating  must 
be  stopped  as  soon  as  the  syrup  has  reached  the  con- 
sistency of  from  40°  to  41°  B. 

This  sugar  has  heretofore  been  mostly  packed  up  in 
cases  of  50  kilogrammes  (110  Ibs.),  and  has  thus  been 
introduced  into  the  market.  But  more  recently  the 

*  But  by  the  use  of  the  improved  vacuum  pump  much  faster. 


252  MANUFACTURE    OF    STARCH,    ETC. 

sugar  has  been  cast  into  blocks  and  loaves,  and  these 
are  afterwards  grated,  and  the  sugar  then  packed  in 
bags. 

The  construction  of  a  very  excellent  sugar-grating 
machine  is  delineated  in  Fig.  42, and  requires  no  further 
description. 

Fig.  42. 


Sugar-grating  machine. 

This  modern  method  of  packing  the  sugar  in  bags 
or  sacks  is  far  more  practical  and  advantageous  than 
the  older  method  of  packing  it  in  boxes,  since  the  sugar 
adheres  to  the  wood  of  the  boxes,  is  hard  to  loosen  from 
the  sides  of  the  cases,  and  hence  much  i*s  irretrievably 
lost. 

Granulated  Starch  -  sugar.  —  The  manufacture  of 
granulated  grape-  or  starch-sugar  was  introduced  by 
Foil  chard  at  Neuilly,  France.  The  transformation 
of  the  starch  into  sugar  is  accomplished  in  the  same 
manner  as  has  already  been  described,  and  of  course  at 
an  increased  temperature  and  greater  atmospheric 


THE    TECHNOLOGY   OF    STARCH-SUGAR.  253 

pressure,  inasmuch  as  a  greater  amount  of  dextrine 
would  be  a  hindrance  to  the  granulation  of  the  sugar. 
The   liquor  being  saturated  with  lime  is  caused  to 
run  through  a  boneblack  filter  in  order  to  impart  to  it 
the  color  of  a  nice  clear  covering  sugar.*     The  filtered 

(liquor  is  thereupon  evaporated  either  by  the  application 
of  Roberts^s  apparatus  or  in  the  vacuum  pan.  This 
manipulation  is  done  in  summer  by  condensing  to  30° 
B.,  in  winter  to  28°  B.  (weighed  while  boiling).  The 
syrup  is  then  run  into  capacious  clearing  tanks,  where 
the  greater  part  of  the  precipitated  gypsum  settles. 
These  tanks  must  be  placed  in  a  cool  location,  or  the 
cooling  process  is  accelerated  by  the  use  of  worms  in 
which  cold  water  circulates,  so  as  to  avoid  fermenta- 
tion. After  the  lapse  of  from  twenty-four  to  thirty 
hours  the  syrup  is  cool  and  clear,  and  is  then  placed 
in  vertical  barrels,  which  are  left  open  above,  and 
whose  bottoms  are  perforated  with  small  holes,  thus 
forming  a  sieve  bottom.  During  the  process  of  crys- 
tallization these  openings  are  kept  closed  with  small 
wooden  pegs  or  taps.  The  barrels  stand  on  the  tra- 
verse joists  of  a  frame-work  which  is  only  30  centi- 
metres (11.8  inches)  high,  over  a  gutter  lined  with 
lead. 

In  the  course  of  from  ten  to  twelve  days  the  crystal- 

*  In  order  to  hasten  the  bleaching  of  the  glucose  during  the  pro- 
.  cess  of  its  manufacture  the  following  treatment  should  be  observed: 
Mix  10  kilogrammes  (22  Ibs.)  of  boneblack  in  50  kilogrammes 
(1 10  Ibs.)  of  sulphuric  acid,  macerating  the  mixture  from  twelve  to 
fifteen  hours,  stirring  it,  and  pouring  the  same  into  the  vessel  in 
which  the  transformation  of  the  starch  into  sugar  is  taking  place. 
To  each  portion  of  sulphuric  acid  thus  applied  boneblack  is  added 
in  the  manner  prescribed.  By  this  method  the  starch-syrup  is  at 
once  bleached. 


254  MANUFACTURE    OF    STARCH,    ETC. 

lization  begins  by  the  formation  of  small  accumula- 
tions in  the  syrup,  which  gradually  increase.  As  soon 
as  the  syrup  is  about  two-thirds  filled  with  crystals, 
the  holes  in  the  bottom  of  the  barrels  are  to  be  opened, 
draining  off  the  molasses,  while  the  soft  crystalline 
accumulations  remain  in  the  barrels.  If  the  crystals 
appear  in  such  a  crowded  state,  that  the  dropping  off 
of  the  molasses  does  not  ensue  freely,  it  should  be 
diluted  with  a  small  portion  of  water. 

As  soon  as  the  draining  off  appears  to  be  finished, 
this  operation  is  perfected  by  placing  the  barrels  in  an 
inclined  position  (45°).  The  molasses  thus  obtained 
is  to  be  again  boiled  in  sulphuric  acid  water,  in  order 
to  transform  the  dextrine  contained  therein  into  sugar.* 

The  granulated  sugar  thus  obtained  is  then  placed 
•on  gypsum  slabs  .to  the  height  of  10  centimetres  (3.9 
inches)  and  dried  in  a  temperature  of  from  22°  to  25° 
C.  (71.6°  to  77°  F.).  By  increasing  the  temperature 
for  this  purpose,  the  crystals  would  melt  in  the  latent 
syrup  and  stick  together.  However,  this  occurrence 
(the  lump  formation)  cannot  be  entirely  avoided,  de- 
spite all  the  possible  care  which  may  be  observed.  If 
it  should  be  noticed  that  the  lower  part  of  the  layer 
begins  to  become  dry  and  white,  it  is  to  be  turned,  so 
that  the  upper  part  is  placed  below  and  experiences 
the  same  change.  > 

In  the  course  of  three  or  four  days  the  sugar  becomes 
perfectly  dry,  and  is  then,  for  the  purpose  of  an  even 
separation,  ground  through  a  sieve,  while  the  lumps 
which  do  not  pass  through  the  sieve  are  ground  between 
a  pair  of  porcupine  rollers.  Usually  the  sugar  is  there- 
upon again  spread  on  gypsum  slabs. 

*  See  also  method  of  centrifuging,  previously  described. 


THE   TECHNOLOGY   OF    STARCH-SUGAR.  255 

Fouchard's  granulated  starch-sugar  forms  loose 
grains,  each  of  them  consisting  of  a  mass  of  small 
rhomboidal  tablets,  grouped  around  a  common  centre. 
This  sugar  is  very  similar  to  our  granulated  cane- 
sugar,  and  is  frequently  used  in  adulterating  it. 

The  Manufacture  of  Grape-syrup  and  Grape-sugar 
from  Grapes  and  Raisins. — For  the  production  of 
grape-sugar  from  grapes,  it  is  best  to  use  the  perfectly 
ripe  fruit  of  the  .white  species,  pressing  the  same  in 
any  suitable  manner.  The  must  thus  obtained  is  heated 
and  mixed  with  finely  ground  terra-alba,  witherite,  or 
chalk,  in  order  to  neutralize  a  part  of  its  tartaric  acid. 
Thereupon  the  liquid  is  heated  to  boiling,  then  left  to 
rest  for  24  hours,  in  order  to  allow  the  precipitation  of 
the  insoluble  salts  which  have  formed. 

The  must,  having  to  a  great  extent  thus  been  freed 
of  its  acid,  is  now  cleared  by  the  application  of  from 
two  to  three  per  cent,  of  its  volume  of  ox-blood  or 
albumen,  skimmed,  and  finally  evaporated  down  to  26° 
B.  The  syrup  thus  obtained  is,  however,  not  yet  per- 
fectly pure,  but  still  contains  mucilaginous  ingredients, 
which  may  be  most  suitably  removed  by  a  prolonged 
depositing.  In  order  to  accomplish  this,  the  grape- 
syrup  is  deposited  in  large  tanks,  and  left  at  rest  for 
some  time,  until  the  impurities  settle  to  the  bottom. 
By  means  of  a  careful  drawing  off  of  the  now  perfectly 
cleared  liquid,  and  by  evaporating  the  same  down  to 
34°  B.,  a  grape-syrup  is  obtained,  which  is  entirely 
applicable  for  most  of  the  purposes  for  which  the  va- 
rious starch-sugars  are  used.  For  improving  wines 
and  apple-cider  such  syrup  excels  all  others,  but  is 
generally  too  expensive. 

Of  this  grape-syrup,  solid  sugar  can  also  be  made, 
by  placing  the  thickly  condensed  syrup  in  crystallizing 


256  MANUFACTURE   OF    STARCH,    ETC. 

vessels,  wherein  after  the  lapse  of  from  three  to  four 
weeks  granulated  crystals  will  become  separated.  The 
non-crystallizable  fruit,  or  mucilaginous  sugar,  is  there- 
upon removed  by  means  of  a  pure  starch-sugar  solution, 
which  is  poured  into  the  forms  which  contain  the 
crystallized  grape-sugar.  The  same  object  can  also 
be  attained  by  means  of  the  centrifugal  apparatus. 

If  real  grape-sugar  is  produced  in  very  small  quanti- 
ties, the  removal  of  the  non-crystallizable  mucilaginous 
sugar  can  be  attained  by  pouring  the  moist  paste  upon 
large  clay  slabs,  over  which  filter-paper  has  been  spread. 

The  yield  of  grape-sugar  from  grapes,  as  is  self- 
evident,  varies  greatly  according  to  the  quality  of  the 
grapes.  On  an  average  it  may  be  accepted,  that  the 
yield  will  result  thus: — 

From  1000  parts  (weighed)  fresh  grapes. 
800     "      of  must. 
200     "      of  syrup. 
140     "      of  crude  grape-sugar. 
60-70     u      of  pure  grape-sugar. 

THE  QUALITY  OF  STARCH-SUGAR.  DETERMINA- 
TION AS  TO  IMPURITIES  AND  ADULTERATIONS 
OF  STARCH-SUGAR. 

Grape  or  starch-sugar  in  its  pure  state  is  hard  and 
white  like  loaf-sugar,  more  or  less  porous,  and  pos- 
sesses withal  a  peculiarly  dull,  not  transparent  appear- 
ance. Anthon's  granulated  sugar, 'known  to  be  the 
best  in  commerce,  contains  95.3  per  cent,  of  anhydrous 
starch-sugar  and  4.7  per  cent,  of  water.  Its  contents 
of  water  amount  therefore  to  but  one  equivalent  and 
not = two  equivalents  (10  weight  per  cent,  of  water), 
as  is  the  case  with  common  sugar.  Grape-sugar 


THE   TECHNOLOGY   OF    STARCH-SUGAR.  257 

makes  its  appearance  but  seldom  in  the  trade  in  a 
pure  state,  is  often  not  even  sufficiently  dry,  but  pos- 
sesses a  greasy  almost  soap-like  consistency,  is  more 
or  less  of  a  yellowish  or  brownish  color  on  account  of 
its  foreign  admixtures,  and  hence  does  not  furnish  a 
transparent  solution. 

The  chemist  C.  Newlauer  analyzed  a  series  of 
grape-sugar  samples  from  various  manufacturing 
establishments,  with  the  following  result.  Above  all 
he  observed,  that  most  of  the  sugars  which  he  tested 
could  hardly  claim  the  title  of  grape-sugars,  by  which 
they  are  known.  Many  of  these  articles  were  not  even 
dry,  but  had  a  soap-like  feel  and  consistency ;  many 
were  not  even  colorless,  and  all  of  them  without  ex- 
ception failed  to  dissolve  clear  in  alcohol.  All  of  the 
specimens  investigated,  even  the  most  nearly  color- 
less samples  of  grape-sugar,  showed  a  more  or  less 
turbid  liquor,  when  dissolved  in  but  little  water  and 
this  mixed  with  strong  alcohol ;  all  this  originated 
from  the  dextrine  yet  remaining  in  the  product,  the 
latter  being  an  intermediate  product  between  dextrine 
and  sugar,  with  an  admixture  of  gypsum.  Solutions 
of  10°  B.  of  these  preparations,  when  placed  in  test- 
tubes  with  capillary  closure,  and  left  exposed  to  the 
air,  developed  very  strong  fungi  vegetations,  while 
solutions  of  crystallized,  pure  cane-sugar,  even  after 
the  lapse  of  months,  showed  scarcely  any  traces  of 
fungi  when  placed  under  the  microscope.  All  of  the 
above  mentioned  moist  preparations  of  soapy  consist- 
ency— and  they  are  not  unfrequeut  in  the  trade — are 
inclined  to  become  mouldy  and  musty.  In  closed 
glass  jars,  some  pieces  soon  become  covered  with 
fungi,  and  on  the  opening  of  the  jars  a  most  nauseat- 
ing smell  was  noticed. 

17 


258 


MANUFACTURE   OF    STARCH,    ETC. 


Dr.  Neiibauer  does  however  by  no  means  assert, 
that  all  the  grape-sugar  of  -commerce,  is  to  be  found 
in  such  a  deplorable  condition,  but  many  of  the  speci- 
mens investigated  by  him  were  of  that  inferior  nature. 
In  the  following  table  the  results  of  the  test  of  thirteen 
different  samples  of  grape-sugar  are  given  : — 


Sp.  KT.  of  the 
solution  of  100 
g.  (3.5  ozs.  av.) 
to  the  litre. 

Dry  sub- 
stance, accord- 
ing to  Balling. 
Per  cent. 

Dry  sub- 
stance in 
starch-sugar. 
Per  cent. 

Non-ferment- 
able sub- 
stances. 
Per  cent. 

Fermentable 
starch-sugar. 

Per  cent. 

Water. 
Per  cent. 

1 

1.0306 

7.609 

78.42 

21.18 

57.24 

21.58 

2 

1.0340 

8.438 

87.25 

23.47 

63.78 

12.75 

3 

1.0300 

7.463 

76.87 

20.67 

56.20 

23.13 

4 

1.0340 

8.438 

87.25 

23.47 

63.78 

12.75 

5 

1.0323 

8.024 

82.84 

23.59 

59.25 

17.16 

6 

1.0325 

8.073 

83.36 

19.90 

63.45 

16.65 

7 

1.0327 

8.122 

83.88 

22.45 

61.43 

16.12 

8 

1.0336 

8.341 

86.21 

21.43 

64.78 

13.79 

9 

1.0329 

8.170 

84.39 

20.29 

64.10 

15.61 

10 

1.0298 

7.413 

76.34 

13.32 

63.02 

23.66 

11 

1.0464 

11.428 

79.72 

20.58 

59.14 

20.28 

13 

1.0325 

8.073 

83.36 

22.70 

60.66 

16.64 

13 

1.0295 

7.341 

75.58 

18.23 

57.20 

24.42 

The  mean  composition  is  :• 

Fermentable  grape  sugar   . 
"Non-fermentable  substances 
Water 


61.08  per  cent. 
20.88    " 
18.04    " 


100.00  per  cent. 

~E.  Sclimid  found  by  his  investigations  of  six  differ- 
ent kinds  of  grape-sugar,  86.6  per  cent,  dry  substance 
and  but  13.4  per  cent,  of  water.  In  the  mean  these 
grape-sugar  samples  furnished  : — 

Fermentable  sugar     . 
Unfermentable  substances . 
Water 


70.1  per  cent. 
16.5         " 
13.4         " 


1 00.00  per  cent. 

Fred  Mohr,  who  investigated  six  different  kinds  of 
grape-sugar,  according  to  Anthem's  method,  found  in 


THE   TECHXOLOGY   OF   STARCH-SUGAR.  259 

these  from  9  to  45  per  cent,  of  impurities.  In  two 
tests  of  fermentation,  which  were  made  with  25  per 
cent,  solutions  of  pure  starch-sugar  of  Anthon's  make, 
and  of  commercial  sugar,  the  indicator  of  the  saccharo- 
meter  sank  to  1.05,  in  the  case  the  first  mentioned,  hence 
a  complete  fermentation  had  ensued  in  this  case,  while 
in  the  case  of  the  commercial  grape-sugar,  after  the 
finished  fermentation,  the  saccahrometer  still  showed  9.5 
per  cent,  of  non-fermentable  substances.  Fred.  Mohr, 
who  is  otherwise  a  supporter  of  Gall's  method,  came 
to  the  conclusion  that  most  of  the  grape-sugar  of 
commerce  "  is  naught  else  but  trash."  In  the  mean 
the  composition  of  grape-sugar  is  determined  accord- 
ing to  Mohr's  test : — 

Fermentable  sugar     .        .        .        .     60.65  per  cent. 
Non-fermentable  substances      .        .     24.00         " 
Water        .        . '.      .        .        .        .     16.00         " 

100.65  per  cent. 

The  glucose  manufacturers — so  thinks  Mohr — seem 
to  have  no  cause  for  improving  their  article  and  making 
progress  in  the  manufacture  of  their  sugar  "  as  long 
as  with  from  16  to  20  per  cent,  non-fermentable  sub- 
stances, they  still  find  consumers  enough." 

The  least  reliable  results  as  to  the  true  amount  of 
sugar  in  commercial  starch-sugar,  are  furnished  by  the 
optical  test,  when  carried  out  by  means  of  one  of  the 
known  "polarization  apparatus"  For  all  practical 
purposes,  the  testing  of  grape-sugar,  as  to  its  contents 
of  real  sugar,  is  most  frequently  accomplished,  by 
finding  out  the  specific  gravity  of  a  saturated  solution 
at  15°  C.  (59°  P.),  according  to  Anthon's  method. 
For  this  purpose  75  grammes  (2.62  ozs.  avoird.)  of  the 
sugar  to  be  tested,  are  first  accurately  weighed  and 


260  MANUFACTURE   OF    STARCH,    ETC. 

then  put  in  a  cylinder  glass,  adding  thereto  75  grammes 
of  distilled  or  rain-water,  or  otherwise  very  pure 
water,  thereupon  leaving  this  mixture  to  stand  for  two 
days,  but  shaking  and  stirring  it  frequently.  There- 
upon a  so-called  0.1  litre  (3.38  flu.  ozs.)  flask  is  used, 
which  is  accurately  measured  and  marked  by  a  line  at 
the  point  where  it  holds  0.1  litre  =  10  centiliters  (the 
flask  holding  generally  something  more  than  10  centi- 
litres), weighing  it  accurately  and  noting  its  weight. 
The  temperature  of  the  sugar  solution  is  then  accurately 
fixed  at  15°  C.  (59°  F.).  Thereupon  from  the  upper 
part  of  the  sugar  solution,  which  is  almost  entirely 
clear,  exactly  0.1  litre  =  10  centilitres  (3.38  fluidozs.) 
are  poured  into  the  weighed  flask,  and  now  this 
flask  is  again  accurately  weighed  with  its  contents. 
Deducting  from  the  total  weight  the  weight  of  the 
flask,  the  net  weight  is  thus  obtained,  of  exactly  0.1 
litre  (3.38  fluidozs.)  or  10  centilitres  of  the  sugar 
solution  at  a  temperature  of  15°  C.  (59°  F.).  If  the 
weight  of  0.1  litre  (338  fluidozs.)  of  this  solution  is  = 
120.6  grammes  (4.22  ozs.  avd.),  that  is  20.6  grammes 
(317.9  grains)  larger  than  0.1  kilogramme  (0.22  lb.), 
then  the  tested  sugar  will  be  entirely  pure,  that  is,  it 
contains  of  foreign  ingredients  0  per  cent,  and  so  on, 
as  can  be  seen  by  the  tabular  statements,  prepared 
by  Anthon. 


THE  TECHNOLOGY  OF  STARCH-SUGAR. 


261 


Table  for  ascertaining  the  purity  of  Grape-Sugar  according  to  the 
method  of  Anthon. 


Specific  grav. 

Amount  of 

Specific  grav. 

Amount  of 

Specific  grav. 

Amount  of 

atlo°C.  (59°  F.) 

foreign  in- 

at 15°  C.  (59°  F.) 

foreign  in- 

at 15°  C.  (590  F.) 

foreign  in- 

of the  saturated 
sugar  solution. 

gredients 
in  the 
starch-sngar. 

of  the  saturated 
sugar  solution. 

gredients 
in  the 
starch-sugar. 

of  the  saturated 
sugar  solution. 

gredients 
in  the 
starch-sugar. 

per  cent. 

per  cent. 

per  cent. 

1.2060 

0 

1.2368 

16 

.2603 

31 

1.2082 

1 

1  2386 

17 

.2618 

•  32 

1.2104 

.         2 

1.2404 

18 

.2633 

33 

1.2125 

3 

1.2422 

19 

1.2649 

34 

1.2147 

4 

1.2440 

20 

.2665 

35 

1.2169 

5 

1.2456 

21 

.2680 

36 

1.2189 

6 

1.2473 

22 

.2695 

37 

1.2208 

7 

1.2489 

23 

.2710 

38 

1.2228 

8 

1.2506 

24 

.2725 

39 

1.2247 

9 

1.2522 

25 

.2740 

40 

1.2267 

10 

1.2535 

26 

1.2755 

41 

1.2284 

11 

1.2548 

27 

.2770 

42 

1.2300 

12 

1.2561 

28 

1.2785 

43 

1.2317 

13 

1.2574 

29 

1.2800 

44 

1.2333 

14 

1.2587 

30 

1.2815 

45 

1.2350 

15 

Anthon  has  thoroughly  studied  the  subject  of  the 
solubility  of  grape-sugar  in  alcohol.  His  experiments 
made  in  this  direction  have  resulted  in  establishing 
the  fact,  that  the  solubility  of  grape-sugar  in  alcohol 
is  in  the  inverse  ratio  of  the  amount  of  water  contained 
in  the  latter;  and  that  a  certain  quantity  of  alcohol 
will  dissolve  so  much  less  sugar,  the  more  water  the 
alcohol  contains. 

For  the  quantitative  determination  of  grape-sugar, 
the  great  chemist,  Gentele,  has  furnished  directions, 
which  rest  on  the  following: — 

a.  That  a  solution  of  cane-sugar  does  not  become 
decomposed  by  an  aqueous  solution  composed  of  1 
part  of  ferrocyanide  of  potassium  (red  prussiate  of 
potash)  and  0.5  part  of  hydrate  of  potash  either  in  a 
common  temperature  or  by  boiling,  and  that  a  very 
small  quantity  of  this  reagent  will  color  the  cane-sugar 
solution  to  a  permanent  strong  yellow. 


262  MANUFACTURE   OF    STABCH,    ETC. 

Z>.  But  that  a  solution  of  grape-sugar  will  slowly 
discolor  the  cited  reagent  in  the  cold,  but  more  rapidly 
in  a  temperature  between  50°  and  60°  C.  (122°  and  140° 
F.),  and  very  quickly  between  60°  and  80°  C.  (140°  and 
176°  F. ),  retaining  this  action  as  long  as  yet  undecom- 
posed  grape-sugar  is  present.  For  a  decomposition  of 
that  quantity  of  Invert-sugar,  which  results  from 
treating  1000  milligrammes  (15  grains)  of  cane-sugar 
with  muriatic  acid,  10,980  milligrammes  (169.4 
grains)  of  ferrocyanide  of  potash  are  necessary;  hence 
10.980  grammes  (169.42  grains)  of  this  salt  for  1  gramme 
(15.43  grains)  of  cane-sugar. 

c.  That  dextrine,  no  matter  how  produced,  does  not 
act  upon  the  same  reagent,  even  when  this  gum  has 
been  treated  under  the  same  conditions  with  muriatic 
acid,  by  which  cane-sugar  is  inverted  by  this  acid. 

d.  That  in  a  solution  of  cane-sugar  in  its  forty-fold 
weight  of  water,  to  which  25  per  cent,  concentrated 
muriatic  acid,  of  the  weight  of  the  sugar,  has  been 
added — all  of  the  cane-sugar  passes  over  into  "  inverted 
sugar,"  when  the  same  is  heated  over  a  water  bath  at 
a  temperature  of  54°  or  55°  C.  (129°.2  to  131°  F.).     In 
order  to  apply  these  facts  for  the  purposes  of  determi- 
nation, a  test  liquid  is  prepared  which  contains  in  100 
cubic  centimetres  (3.38  fluidounces),  10.980  grammes 
(169.42    grains)    red    prussiate   of   potash,    and    5.5 
grammes  (84.86  grains)  hydrate  of  potash.     Now  to 
prove  the  presence  of  grape-sugar  in  cane-sugar,  1 
gramme  of  the  latter  is  dissolved  in  40  cubic  centi- 
metres (10.8  fluidrachms)  water,  the  solution  heated 
to  70  C.  (148°  F.),  and  0.1  cubic  centimetre  (.027  flui- 
drachms) added  of  the  test  liquid.     If  the  color  of  the 
latter  disappear  right  off,  then  a  good  deal  of  grape- 
sugar  is  present. 


THE   TECHNOLOGY   OF   STARCH-SUGAR.  263 

In  conclusion,  it  may  be  deemed  of  interest  to  men- 
tion here,  how  to  test  the  presence  of  grape-sugar  in 
honey  and  manna  when  adulterated  with  that  article. 
This  can  be  easily  determined  from  the  fact,  that  since 
neither  starch-sugar  nor  starch-syrup  is  ever  entirely 
free  from  gypsum,  and  since  honey  and  manna  never 
contain  even  a  trace  of  gypsum,  hence  the  presence  of 
the  latter  mineral  furnishes  ample  proof  of  such  an 
adulteration. 

APPLICATION  OF  GLUCOSE  AND  GRAPE-SUGAR. 

The  most  important  use  for  grape-sugar  is  found  in 
the  improvement  of  wiries,  for  the  purposes  of  Gall- 
izing  and  Petiotizing  them.  Although  there  is  "no  ap- 
plication known  for  which  grape-sugar  is  used,  that 
could  not  be  equally  as  well  accomplished  by  the  use 
of  common  cane-sugar,  yet  since  this  article  is  far 
more  expensive  than  the  best  grape-sugar,  it  is  in  the 
interest  of  the  wine-growers  to  use  the  latter  article,  pro- 
vided the  grape-sugar  be  pure.  Gall  and  Petiot  have 
proposed  to  use  for  the  improvement  of  wines  exclu- 
sively, the  so-called  grape-sugar.  In  some  countries, 
the  syrup  of  glucose  finds  much  application  in  the  art 
of  brewing  beer,  etc.,  for  the  distilling  of  ardent  spirits, 
and  as  an  admixture  to  honey  and  sugar-house  syrups. 
It  is  also  used  in  large  quantities  by  confectioners  and 
candy-manufacturers.  For  the  preserving  of  fruits, 
and  for  the  fabrication  of  fruit-syrups,  etc.,  the  article 
"  imponderable  syrup"  serves  its  purpose  well.  And 
last  but  not  least,  grape-sugar  furnishes  the  raw  material 
for  the  production  of  "sugar  coloring"  an  article  used 
for  imparting  the  brown  color  to  cordials,  liquors,  wine, 
vinegar,  rum,  and  cognac,  and  is  also  frequently  ap- 


264 


MANUFACTURE   OF    STARCH,    ETC. 


plied  to  give   tone  to   beer   and    other   beverages  of 
malt,  etc. 

Description  of  a  Glucose  and  Starch-sugar  Manufac- 
tory.— The  following  sketches  (Figs.  43,  44,  45)  repre- 
sent a  very  suitable  arrangement  for  the  construction 

0 

Fig.  43. 


Glucose  factory  of  Noback  Bros.  &  Fritze,  in  Prague  (Bohemia). 

of  a  glucose  manufactory,  which  in  a  comparatively 
limited   space   contains  only  the  most  indispensable 
apparatus  and  utensils,  arranged  in  a  highly  practical 
manner. 
7,  is  the  boiler-house ;  II,  the  cooling-room ;  III, 


THE   TECHNOLOGY   OF   STARCH-SUGAR. 


265 


the  laboratory;   IV,  the  potato-starch  manufactory; 
and  V,  the  warehouse. 


Fig.  44. 


\0 


Glucose  factory  of  Noback  Bros.  &  Fritze,  in  Prague  (Bohemia). 
Ground  plan. 

The  inner  appointments  of  this  establishment  con- 
sist of  the  following  : — 

a,  starch-stirring  vat;  mean  diameter  2  metres  (6.56 
feet) ;  height  1.60  metre  (5.25  feet). 

5,  two  boiling-vats;  mean  diameter  2  metres  (6.56 
feet) ;  height  3  metres  (9.84  feet). 

c,  liquor  reservoir;  mean  diameter  2.5  metres  (8.20 
feet)  ;  height  1.5  metre  (4.92  feet). 

d,  two  Montejus,  each  having  an  automaton ;  diame- 
ter 0.80  metre  (2.62  feet) ;  height  2  metres  (6.56  feet). 


2G6 


MANUFACTURE   OF   STARCH,    ETC. 


e,  the  steam  filter-press. 

jf,  two  sugar-liquor  reservoirs  a  1  x  2  x  1J   metre 
(3.28  x  6.56  x  4.92  feet). 

y,  vacuum  pan,  diameter  1.60  metre  (5.25  feet). 

Fig.  45. 


Glucose  factory  of  Noback  Bros.  &  Fritze,  in  Prague  (Bohemia). 

7z,  four  filters,  1.35  metre  (4.43  feet)  high  ;  upper  dia- 
meter 0.80  metre  (2.62  feet) ;  lower  diameter  0.70  metre 
(2.3  feet). 

i,  water-reservoir. 

&,  air-pump. 

Z,  two  cooling-vats  (bacs). 

m,  three  coolers  a  I|xl|x0.65  metre  (4.92x49.2 
x  2.13  feet). 

/i,  wooden  closet  0.40  metre  (1.31  feet)  wide. 


THE   TECHNOLOGY   OF   STARCH-SUGAR.  267 

The  grape-sugar  products  of  commerce,  whether  in 
liquid  or  solid  form  of  aggregation,  contain  hardly  ever 
more  than  60  per  cent,  of  starch-sugar.  The  remainder 
is  composed  of  water,  dextrine,  and  of  diverse  interme- 
diate products.  Thus  far  there  is  but  one  exception 
to  this  general  rule,  namely,  Anthon's  crystallized 
starch-sugar.  His  product  contains  but  one  equivalent 
of  water. 


268  MANUFACTURE   OF    STARCH,    ETC. 


SECTION  III. 

THE  MANUFACTURE  OF  SUGAR-COLOR  (COULEUR). 

BY  the  designation  sugar-color,  or  couleur,  at  present 
is  known  that  article  which  formerly  was  termed  tinc- 
ture of  sugar,  a  concentrated  solution  of  burnt  sugar, 
or  caramel.  Formerly  it  was  merely  used  by  the  manu- 
facturers of  cordials  for  imparting  to  these  products  a 
brown  color.  But  since  imitations  of  rum  and  cognac 
are  being  made  in  extraordinarily  large  quantities, 
this  "color"  serves  as  an  important  factor  in  color- 
ing these  alcoholic  beverages,  and  also  when  an 
erroneous  taste  desires  the-  beer  to  be  of  a  dark  hue, 
this  couleur  is  applied  to  gratify  this  mistaken  prefer- 
ence. "Vinegar  too  is  frequently  colored  with  this  in- 
gredient in  order  to  make  it  resemble  the  French 
article  or  that  made  of  beer.  After  the  application  for 
these  various  purposes  it  will  be  obvious  whence  the 
terms  beer-couleur,  rum-couleur,  wliiskey -couleur  l  etc., 
originate. 

The  fabrication  of  couleur  from  sugar  has  reached 
in  modern  times  such  an  important  place  in  commerce 
that  it  forms  quite  an  item  in  the  annals  of  industrial 
statistics. 

As  has  already  been  stated  sugar-couleur  is  divided 
into  two  different  kinds,  viz.,  those  for  spirituous 
liquors  (rum-couleur)  and  beer-couleur.  The  former 
is  used  for  the  coloring  of  alcoholic  liquors  (rum,  arrac, 
whiskey,  etc.),  the  latter  for  coloring  beer,  ale,  wine, 


THE   MANUFACTURE   OF   SUGAR-COLOR.  269 

vinegar,  sauces,  and  even  serves  as  a  coloring  matter 
for  coffee-essences.  Both  these  coloring  substances 
are  at  present  prepared  from  the  less  expensive  grape- 
sugar,  and  for  this  reason  the  "  sugar-couleur"  is  of  late 
rated  at  a  much  lower  quotation  than  formerly,  notwith- 
standing the  fact  that  the  quality  of  the  product  re- 
mains unchanged. 

The  process  of  manufacturing  couleur,  although  very 
simple,  requires  accuracy,  experience,  and  talent,  so 
that  but  few  establishments  can  furnish  a  thoroughly 
approved  article. 

This  coloring  matter  is  generally  produced  by  the 
heating  of  starch-sugar  in  a  kettle  until  it  forms 
a  dark-brown  mass.  After  sufficiently  cooling  off, 
water  is  added  in  order  to  dissolve  the  substance  to  a 
dense,  dark-brown  liquid.*'  This  is  what  is  termed 
couleur. 

The  sugar  melts  while  being  heated,  the  melted  syrup 
colors  gradually  more  and  more  brown  while  puffing 
up  and  squirting.  For  this  reason  the  kettle  should 
be  very  roomy  compared  to  its  contents,  and  frequent 
stirring  is  also  required.  This  operation  ensues  under 
the  development  of  dense,  whitish  vapors  of  an  empy- 
reumatic  smell.  At  first  the  fire  may  be  allowed  to 
burn  in  a  lively  manner,  but  toward  the  end  of  the 
process  it  must  be  modified  as  the  melted  mass  might 
otherwise  become  carbonized.  The  time  when  the  fire 
must  be  diminished  is  known  to  the  expert  by  the  color 
of  the  substance.  It  must,  when  taken  upon  a  wooden 
spatula  congelate  to  a  dark-brown  lustrous  mass,  and 
flow  off  from  the  stirrer  like  tar  (thread-like).  A  wire 

*  Glucose  is  not  so  well  adapted  for  this  purpose  as  starch-sugar, 
on  account  of  its  larger  contents  of  dextrine. 


270  MANUFACTURE   OF    STARCH,    ETC. 

dipped  into  the  kettle  must  become  thickly  covered, 
and  form  blisters.  The  smell  and  color,  too,  are  guides 
to  the  expert. 

According  to  the  chemist  Krotke,  of  Berlin,  rum- 
couleur  is  manufactured  in  the  following  manner : — 

The  sugar  syrup,  almost  entirely  free  from  dextrine 
and  condensed  to  36°  B.  (weighed  hot)  and  filtered, 
is  while  yet  hot  directly  applied  for  making  the 
couleur.  In  this  way  much  is  saved  in  fuel  and  labor. 
But  if  circumstances  should  not  permit  of  this  method, 
then  the  solid  sugar  is  first  broken  up  into  pieces 
weighing  about  5  kilogrammes  (11  Ibs.)  and  thus  used 
for  burning.  For  operating  on  a  larger  scale  from 
100  kilogrammes  (220  Ibs.)  to  200  kilogrammes  (440 
Ibs.)  are  usually  applied  at  once.  The  boiler  used  for 
this  purpose,  made  of  strong  wrought  iron,  is  to  be 
1  metre  (3.28  feet)  High,  and  its  upper  diameter  meas- 
uring 1.5  metres  (4.92  feet).  The  bottom  of  the  same 
is  to  be  somewhat  stouter  than  the  sides,  and  should 
be  spherical.  To  the  kettle  an  iron  stirring-appa- 
ratus is  affixed,  which  must  be  kept  in  motion  during 
the  time  the'  fire  is  kept  up.  This  apparatus  cuts 
accurately  as  far  down  as  the  bottom,  so  that  no  part 
of  the  sugar  can  burn  to  ashes.  During  the  opera- 
tion of  burning  the  sugar,  a  penetrating  disagreeable 
odor  is  developed;  and  for  this  reason  such  kettles  are 
provided  with  a  wooden  lid  and  a  chimney  for  carry- 
ing off  these  vapors.  From  the  forepart  of  the  kettle, 
the  lid  can  be  removed,  while  the  other  part  with  the 
ventilator  chimney  is  fixed  and  permanent. 

The  burning  of  the  rum-  or  alcohol-couleur  is  per- 
formed thus :  From  100  to  200  kilogrammes  (220  to 
440  Ibs.)  of  crushed  starch-sugar,  or  rather  hot  sugar 
syrup,  are  placed  in  the  kettle,  and  the  fire  is  started 


THE   MANUFACTURE   OF    SUGAR-COLOR.  271 

thereunder.  As  soon  as  the  sugar  is  melted,  and  the 
syrup  becomes  liquid,  the  stirring  operation  com- 
mences. Usually  one  laborer  is  sufficient  for  this 
manipulation  and  is  able  to  make  from  500  to  600  kilo- 
grammes (1100  to  1320  Ibs.)  of  couleur  in  a  day. 

As  soon  as  the  melted  or  liquefied  sugar  begins  to 
boil,  3  kilogrammes  (6.6  Ibs.)  of  crystallized  soda  are 
added  for  every  100  kilogrammes  (220  Ibs.)  of  sugar. 
The  soda  is  to  be  in  pieces  of  the  size  of  a  walnut, 
and  to  be  added  gradually.  A  handful  of  soda  is 
thrown  into  the  boiling  sugar;  this  will  cause  the 
mass  to  rise  under  great  ebullition  and  it  must  first 
be  made  to  descend  again,  by  stirring,  before  more 
soda  is  added.  After  the  soda  has  all  been  disposed 
of  in  this  manner,  the  burning  is  continued  over  a 
good  fire.  The  liquid  becomes  more  and  more  brown. 
As  soon  as  a  burning  smell  is  observed,  the  lid  is  to 
be  raised  somewhat.  The  expert  workman  knows  at 
once  by  the  color  of  the  substance,  when  the  heating 
and  the  burning  operations  have  to  be  interrupted.  If 
the  test  has  proved  that  the  sugar  is  sufficiently  burnt, 
then  hot  water  is  added.  To  every  100  kilogrammes 
(220  Ibs.)  of  sugar,  50  litres  (13.20  gals.)  of  water 
may  be  used.  This  must  be  poured  in  quickly,  while 
keeping  up  a  lively  stirring.  Thereupon  the  couleur 
is  weighed  in  its  hot  state  by  an  hydrometer.  If  the 
couleur  shows  a  consistency  of  35°  B.,  it  will  be  ready 
for  sale ;  if  it  shows  more  degrees,  then  more  water 
should  be  added;  but  should  the  article  indicate  but 
34°  or  less,  then  it  must  be  left  to  condense  for  several 
minutes  longer. 

The  fire  is  now  removed  from  under  the  kettle,  the 
couleur  drawn  off  and  placed  in  the  cooling  vat.  The 
latter  is  of  pine-wood,  and  1  metre  (3.28  feet)  high  and 


272  MANUFACTURE   OF    STARCH,    ETC. 

of  2  metres  (6.56  feet)  diameter.  Upon  the  vat  a 
basket  of  willow,  1  metre  wide  and  0.25  metre  (9.84 
inches)  high,  is  placed,  over  which  a  large  cloth  of 
cotton  of  a  thin  texture  is  placed,  and  through  this 
filter  the  couleur  is  poured,  in  order  to  strain  off  the 
cinders  which  may  have  formed  during  the  operation. 

The  finished  contents  of  each  kettle  should  be 
tested,  as  to  its  reaction  on  alcohol  of  82  per  cent. 
To  this  end  a  test-tube  is  filled  to  one-half  of  its 
capacity  with  such  82°  alcohol,  pouring  one  drop  of 
the  finished  couleur  therein  and  shaking  the  same  well. 
If  the  alcohol  remains  clear,  the  couleur  maybe  stored 
away  as  80  per  cent.,  but  in  case  the  alcohol  turns 
even  in  the  least  turbid  or  dull,  then  the  couleur  is 
stored  away  in  the  reservoir  for  that  of  lower  per- 
centage. 

The  process  of  manufacture  of  beer-couleur  (also 
called  wine-couleur)  is  given  by  Krotke,  the  technical 
chemist,  as  follows: — 

The  operation  is  very  simple,  so  that  every  wine 
grower  or  brewer  may  prepare  his  own  supply,  by 
getting  the  requisite  raw  materials.  In  order  to  ob- 
tain practice,  a  commencement  should  be  made  with 
small  quantities.  For  the  first  trial  5  kilogrammes 
(11  Ibs.)  suffice.  These  5  kilogrammes  of  starch-sugar 
are  put  into  a  kettle  and  melted  over  a  brisk  fire.  As 
soon  as  the  sugar  melts,  it  begins  to  bubble  and  to 
rise ;  when  it  will  be  necessary  to  stir  with  a  wooden 
paddle,  so  that  the  mass  does  not  boil  over.  If  this 
is  not  sufficient,  a  little  butter  of  the  size  of  a  pea  is 
added,  and  if  this  does  not  have  the  desired  effect, 
then  the  fire  must  be  diminished.  The  sugar  is  now 
left  to  boil  until  it  begins  to.  burn.  This  is  perceived 
by  a  penetrating  smell,  which  causes  pain  to  the  eyes. 


THE    MANUFACTURE   OF    SUGAR-COLOR.  273 

At  this  juncture  100  grammes  (3.5  ozs.  avoir.)  of 
coarse  carbonate  of  ammonia  are  added,  and  continuing 
the  boiling  while  constantly  stirring.  Thereupon  the 
boiling  is  kept  up  over  a  gentle  fire,  until  the  sugar 
becomes  almost  stiff,  and  it  is  difficult  to  stir  the  same. 
Then  the  testing  begins.  A  small  stick  of  wood,  of 
the  size  of  a  penholder,  is  placed  in  the  boiling  mass. 
The  substance  which  adheres  to  this  stick  is  quickly 
placed  in  a  glass  of  cold  water,  and  thus  suddenly 
cooled  off.  If  the  cooled-off  coulcur  is  entirely  brittle, 
and  can  be  easily  bruised  between  the  fingers,  it  is 
finished.  Should  the  sample  still  appear  very  hard, 
and  its  taste  be  sweet,  the  burning  process  must  be 
continued  until  this  sweetish  taste  disappears  and  the 
sample  proves  to  be  brittle.  The  manipulation  on  a 
larger  scale  is  essentially  the  same. 

The  couleur  after  cooling  off  is  filled  into  bottles 
and  barrels. 

If  the  sugar  is  of  a  good  quality  and  the  operation 
properly  conducted,  a  fine  coloring  substance  of  inten- 
sive quality  is  obtained,  which  will  color  all  light  malt 
liquors  brown,  and  which  imparts  to  white  wines  a 
fiery  golden-yellow  hue,  and  red  wines  will  obtain  a 
darker  shade  by  its  application. 

With  this  wine-  or  beer-couleur,  spirits  of  a  lighter 
percentage  may  be  also  colored.  Couleur  prepared 
with  soda  is,  however,  not  suitable  for  coloring  vine- 
gars, because  the  humid  substance,  which  is  formed 
by  the  action  of  the  soda  upon  the  sugar,  is  separated 
by  the  acetic  acid  forming  a  combination  with  the  soda. 

The  following  receipt,  furnished  by  Professor  Otto, 
is  the  basis  of  directions  for  the  manufacture  of  sugar- 
couleur :  140  kilogrammes  (308  Ibs.)  of  yellowish  starch- 
sugar  are  melted  in  an  iron  kettle.  After  complete 


274  MANUFACTURE    OF    STARCH,    ETC. 

liquefying,  4  kilogrammes  (8.8  Ibs.)  crystallized  soda 
are  added,  and  the  melting  is  continued  until  the  above 
described  phenomena  ensue,  after  which  the  boiling  is 
to  be  continued  over  a  slow  fire,  for  five  minutes 
longer.  After  sufficiently  cooling  off',  from  71  to  73 
litres  (18,744  galls,  to  19,272  galls.)  of  water  are  added, 
during  whicfc^the  stirring  is  not  to  be  interrupted.  The 
entire  operation** requires  but  two  hours,  and  an  excel- 
lent article  is  the  result. 


PART  III. 

THE  MANUFACTURE  OF  DEXTRINE. 


SECTION  I. 

THE  CHEMISTRY  OF  DEXTRINE. 

History,  Literature,  and  Terminology. — In  the  year 
1810,  Bouillon  Lagrange  made  the  important  discovery 
that  starch,  when  slightly  roasted,  acquires  the  pro- 
perty of  being  soluble,  in  cold  water,  into  a  muci- 
laginous (gum-like)  liquid.  This  discovery  was  acci- 
dentally made  at  the  time  of  the  continental  blockade, 
when  the  price  of  gum-arabic  was  unusually  high. 
This  circumstance  gave  inducement  for  applying  the 
terrified  or  roasted  starch  as  a  surrogate  for  the  Ara- 
bian and  Senegal  gums  in  finishing  calicoes. 

Considering  the  circumstance,  that  roasted  starch 
possesses  such  properties,  which  make  it  sometimes  a 
perfect  substitute  in  lieu  of  the  always  more  expensive 
foreign  gums,  the  discovery  of  Bouillon  Lagrange  ap- 
pears to  be  of  great  importance,  and  in  case  of  emer- 
gency the  oriental  product  may  be  entirely  dispensed 
with. 

At  first  the  starch  was  roasted  in  iron  kettles  or 
drums,  which,  especially  in  the  former  case,  caused 
many  inconveniences.  In  order  to  avoid  these,  Dingier, 
in  1820,  proposed  to  roast  the  starch  in  whole  pieces 


276  MANUFACTURE    OF    STARCH,    ETC. 

on  iron  plates,  in  a  heated  bake-oven.  With  the  view 
of  retaining  the  product  still  more  gnm-like,  Kurrer 
performed  the  roasting  in  an  iron  vessel  over  a  coal 
fire,  by  constantly  stirring  the  starch  mass,  so  that  the 
starch  ran  together  into  a  brownish  substance,  whose 
watery  solution,  when  carefully  evaporated  to  dryness, 
assumed  a  dark  brown  lustrous  appearance,  similar  to 
rosin.  Since  1829,  Guibourt,  a  French  chemist,  has 
made* many  experiments  and  investigations  respecting 
the  production  of  dextrine.  Doeberreiner  found  that 
the  solubility  of  the  roasted  starch  is  dependent  on  the 
temperature  maintained  during  the  process  of  roasting, 
while  Payen,  already  as  early  as  1834,  proved,  that  the 
most  suitable  temperature  for  the  roasting,  in  order  to 
produce 'the  dextrine,  is  from  200°  to  210°  C.  (392°  to 
410°  F.),  and  that  dextrine  obtained  at  these  degrees 
of  heat  will  dissolve  most  perfectly. 

An  explanation  of  the  transformation  of  starch  by 
means  of  roasting  was  easily  rendered  during  the 
years  immediately  preceding  1829.  As  starch,  ac- 
cording to  the  investigations  made  by  Loewenhoek 
(1816),  and  somewhat  later  by  Guerin  iary,  con- 
sisted of  granules  whose  hulls  and  contents  chemi- 
cally vary;  and  Easpail  believed  he  had  found  (1825) 
that  the  hulls  are  indissoluble  in  water,  while  their 
contents  are  soluble  therein,  and  are  identical  with  gum. 
At  that  time  it  was  accepted,  that  by  the  roasting  of 
starch,  the  hulls  are  emptied  of  their  granules,  and 
their  contents  become  soluble  in  water,  and  after 
evaporating  such  a  solution  remains  as  a  precipitate. 
But  Lassaigne  had  already,  in  1820,  drawn  attention 
to  the  fact,  that  starch  did  not  contain  any  gum,  since 
by  heating  it  with  nitric  acid,  no  pyro-mucic  acid,  as 
in  the  case  of  natural  gum,  was  produced,  but  oxalic 


THE   CHEMISTRY    OF    DEXTRINE.  277 

acid.  Fritzsche,  in  1841,  proved  most  decidedly  that 
no  substance  soluble  in  water  is  contained  in  starch, 
while  Guibourt  already,  in  1829,  perceived  the  differ- 
ence in  the  structure  of  the  starch  granules  depending 
on  the  various  states  of  aggregation  of  one  and  the 
same  substance.  The  ideas  hitherto  entertained  as  to 
the  origin  of  dextrine  from  starch  during  the  roasting 
process,  became  thus  untenable,  more  especially  when 
soon  thereafter  such  authorities  as  Pay  en,  Fritzsche, 
Persoz,  Schleiden  von  Mohl  and  Ncegeli  explained  that 
.  pure  starch  was  of  an  identical  composition,  and  that 
only  the  inner  strata  of  the  starch  granules  contain  a 
larger  quantity  of  water,  and  are  of  a  lesser  density, 
than  the  outer  layers.  By  this  discovery  it  was  at 
the  same  time  ascertained  that  dextrine  is  not  a  pre- 
paration'separated  from  the  starch  by  roasting,  but  is 
first  formed  by  the  roasting.  This  view  is  even  to 
this  day  the  only  correct  one. 

The  literature  pertaining  to  dextrine  and  its  manu- 
facture tends  to  the  year  1811,  but  extensive  treatises 
on  this  subject  have  never  yet  been  published  in  book 
form,  while  the  magazine  literature  respecting  this 
article  is  indeed  fertile  enough. 

The  term  dextrine  originated  with  Biot  and  Persoz 
who,  in  1833,  proved  that  it  essentially  differs  from 
Senegal  or  Arabian  gum,  and  whereas  the  solution  of 
dextrine  does  not  turn  off  the  surface  of  the  polarized 
rays  to  the  left,  but  towards  the  right  side  ("dexter"), 
and  this  it  does  more  powerfully  than  any  known  or- 
ganic solution,  and  hence  they  gave  to  this  product 
the  name  dextrine,  a  name  which  Berzelius  reproved 
and  criticized  for  scientific  reasons,  because  hundreds 
of  substances  could  perhaps  be  found  possessing  this 
same  peculiarity.  Dextrine  is  also  called  dextrine- 


278  MANUFACTURE    OF    STARCH,    ETC. 

gum,  fruit-gum,  roasted  starch,  starch-gum,  steamed- 
gum,  Amidon- grille,  Leiocome,  Leiogomme,  Gomme 
d>  Alsace,  Qommline,  etc. 

SUBSTANCE  AND  NATURE. 

Biot  and  Persoz  believed  at  first  that  dextrine  was 
not  at  all  a  product  of  the  action  of  sulphuric  acid  on 
starch,  but  that  it  pre-existed  in  the  latter  as  dextrine, 
and  merely  issued  from  the  broken  hulls  by  the  bursting 
of  the  starch-granules  during  the  process  of  boiling  in  a 
moderate  quantity  of  pure  acidulated  water.  In  oppo- 
sition to  this  doctrine,  Payen  and  Persoz,  in  1833,  con- 
sidered dextrine  as  being  not  a  simple  chemical  body, 
but  a  mixture  of  three  different  substances,  i.  e.,  of 
starch-sugar,  being  soluble  in  alcohol,  and  two  other 
substances  indissoluble  in  alcohol,  which  two  latter 
comprise  the  dextrine  of  Biot  and  Persoz.  They  based 
their  opinion  on  the  fact,  that  that  part  of  dextrine  not 
soluble  in  alcohol,  after  drying,  when  mixed  with  cold 
water,  only  partially  dissolves  therein,  while  one  part 
remains  an  indissoluble  residuum.  Meanwhile  dex- 
trine or  starch-gum  is  nevertheless  to  be  considered  as 
a  specific  intimate  ingredient  of  plants,  and  the  above- 
mentioned  part  which  is  indissoluble  in  water  is  to  be 
considered  as  an  impurity  thereof,  perhaps  as  particles 
of  starch,  that  is  as  starch  particles,  which  have  not 
yet  passed  over  into  dextrine,  or  perhaps  as  a  peculiar 
intermediate  link  between  starch  and  dextrine. 

Dextrine  is  always  composed  of  the  same  elementary 
bodies,  no  matter  in  what  manner  it  may  have  been 
produced  or  formed,  and  despite  the  various  physical 
modifications  in  which  it  occurs,  whether  it  has  been 


THE    CHEMISTRY    OF    DEXTRINE.  279 

produced  by  sulphuric  acid,  diastase,  potash,  etc.     It 
always  corresponds  to  the  formula: — 

Ci2HioO10  (or  according  to  the  new  mode  C^H^CX) 
and  hence  is  of  the  same  composition  as  starch. 

ORIGIN  AND  FORMATION. 

Dextrine  appears  in  nature  not  generally  diffused 
throughout  the  vegetable  kingdom,  but  it  occurs,  how- 
ever, mostly  in  small  quantities  in  many  plants.  It  seems 
to  act  an  important  part  in  the  development  of  plants, 
especial Ij7  in  those  parts  of  plants  in  which  a  new  for- 
mation of  the  cells  takes  place.  For  this  reason  many 
physiologists,  for  instance  Schleiden,  deem  dextrine  to 
be  really  that  part  of  the  plant  by  which  new  plants  are 
formed. 

Grain  always  contains  certain  quantities  (4  to  7  per 
cent.)  of  dextrine. 

According  to  analytical  tests — 

Air-dried  wheat  contains  4.5    per  cent,  dextrine. 
Wheat  bran  4-         5.52         "  « 

Rye  bran  "         779         "  " 

Barley  "         6.55         '•  " 

Malt  "         8.23         "  " 

Dextrine  is  also  frequently  found  in  larger  quanti- 
ties as  the  product  of  transformation  of  grain-starch 
in  bread,  in  beer,  and  in  many  other  articles  of  food 
made  of  grain. 

In  the  animal  kingdom  dextrine  is  found  in  the 
blood,  muscles,  spleen  and  liver,  but  more  especially 
of  those  animals  which  are  fed  with  grain. 

When  dry  starch  is  heated  to  a  temperature  of  from 
212°  to  275°  C.  (413.6°  to  527°  F.)  and  in  this  tempe- 
rature kept  for  some  time,  it  attains  gradually  the 


280  MANUFACTURE    OF    STARCH,    ETC. 

color  of  yellow,  brownish-yellow,  or  yellowish-brown, 
and  thus  becomes  roasted  gum,  or  dextrine. 

By  treating  starch  in  diluted  acids  or  by  the  action 
of  the  diastase  (malt  extract),  dextrine  is  likewise 
obtained. 

The  solution  of  the  diastase  is  capable  of  trans- 
forming starch — especially  at  a  temperature  of  from 
70°  to  75°  C.  (158°  to  167°  P.),  into  dextrine  and 
starch-sugar,  i.e.,  it  possesses  at  this  temperature  the 
highest  degree  of  potency. 

In  general,  however,  the  action  of  the  diastase  on 
starch  is  limited,  that  is  in  so  far  as  it  shows  its  action 
at  all,  only  between  —10  and  +80°  C.  (14°  and  176°  P.). 
That  the  formation  of  glucose  is  always  preceded  by 
that  of  dextrine,  has  been  already  amply  set  forth,  and 
nothing  remains  to  be  said  in  this  connection,  but  that 
neither  of  these  products  originates  exclusively,  but 
that  besides  dextrine,  sugar  is  always  formed  and  the 
reverse. 

CHEMICAL  PROPERTIES. 

Dextrine  is  an  hydrate  of  carbon  of  the  same  ele- 
mentary composition  as  starch,  i.  e.,  C12H10O12 ;  or  ac- 
cording to  the  new  mode  C6H10O, ;  being  formed  by 
the  heating  of  the  starch,  but  not,  as  was  formerly 
erroneously  believed,  separated  therefrom.  Payen  had 
furnished  the  proof  as  early  as  1836,  that  dextrine  in 
its  various  modifications  is  of  the  same  composition, 
whether  it  be  formed  by  the  wet  process,  by  the  action 
of  acids,  diastase,  or  by  alkalies,  etc.,  or  by  the,  mere 
heating  (roasting)  of  the  starch.  Professor  Otto  of 
Brunswick,  on  the  other  hand,  is  of  opinion,  that  the 
"  roasted  starch"  is  not  identical  with  that  article, 


THE    CHEMISTRY    OF    DEXTKIXE.  281 

which  has  been  produced  by  the  aid  of  the  designated 
chemical  ingredients.  The  chemically  pure  dextrine 
furnishes  a  perfectly  white,  amorphous,  tasteless  and 
odorless  powder  of  1.52  specific  gravity.  It  dissolves 
in  cold  water  completely,  and  forms  a  glutinous,  muci- 
laginous neutral  solution,  which  is  colored  dark  red 
by  iodine.  This  coloring  disappears  by  heating  it  to 
40°  C.  (104°  F.),  but  reappears  after  cooling  off.  The 
dextrine  of  commerce  when  dissolved  leaves  twelve  or 
more  per  cent,  of  unchanged  or  burnt  starch  as  a 
residuum. 

By  applying  diluted  acids — whether  sulphuric  acid, 
muriatic  acid,  or  acetic  acid  is  used — dextrine  becomes 
partly  transformed  into  grape-sugar  (dextrose)  when 
being  heated,  and  while  absorbing  water.  This  is 
likewise  the  case  with  the  action  of  diastase  or  malt 
(at  a  temperature  of  from  60°  to  75°  C.  =  140°  to  Ib7° 
F.),  however  only  to  a  certain  limit.  In  absolute 
alcohol  and  in  ether,  dextrine  is  indissoluble.  In  an 
alkaline  copper  solution  (Fehl ing's  solution),  dextrine 
when  being  heated  does  not  separate  at  once  protoxide 
of  copper,  but  by  continued  boiling  of  the  mixture  it 
precipitates  in  small  portions.  With  bromide,  and 
oxide  of  silver,  dextrine  may  be  changed  into  dextrine- 
acid.  Many  metal-oxides,  while  being  insoluble  in 
water,  are  soluble  in  a  solution  of  dextrine,  especially 
when  potash  is  present. 

It  has  frequently  of  late  been  a  matter  of  inquiry, 
whether  dextrine  is  fermentable.  Recent  investiga- 
tions in  this  direction  have  clearly  proven  that  dex- 
trine by  itself  is  not  fermentable.  A  pure  solution  of 
dextrine,  mixed  with  beer  yeast,  does  for  this  reason  not 
ferment. 

The  influence  of  an  increased  temperature  on  dex- 


282  MANUFACTURE    OF    STARCH,    ETC. 

trine  has  been  thoroughly  investigated,  and  the  results 
attained  in  this  direction  are  as  follows:  1,  that  dex- 
trine exposed  to  a  higher  temperature  in  an  indifferent 
gaseous  substance  (i.  e.,  in  an  inert  gas,  loaded  with 
moisture)  transforms  into  sugar;  2,  that  there  by  as 
much  more  glucose  is  formed,  the  more  acetous  the 
starch  is  that  is  applied. 

Musculus  has  made  within  the  decade  now  passed 
some  highly  interesting  experiments  respecting  solu- 
ble starch  and  global ous  dextrine. 

Qlobulous  dextrine  is  the  designation  of  a  substance 
which  is  indissoluble  in  cold  water,  and  is  obtained  by 
the  dissolving  of  starch  in  boiling  acid  water,  and  by 
neutralizing  the  acid,  and  evaporating  it  into  syrup. 
It  was  deposited  therefrom  in  abundant  quantities  of 
granules,  which  are  not  soluble  in  cold  water,  but  in 
such  of  a  temperature  of  50°  C.  (122°  F.),  and  hence 
can  be  easily  freed  of  the  adhering  dextrine  and 
glucose  by  washing.  After  a  small  amount  of  the 
granules,  of  which  it  consists,  has  been  extracted  by 
alcohol,  a  pure  soluble  starch  is  obtained,  consisting  of 
granules  of  the  shape  of  the  original  starch  used. 


THE    TECHNOLOGY    OF    DEXTRINE.  283 


SECTION  II. 

THE  TECHNOLOGY  OF  DEXTRINE. 

THE  MANUFACTURE  OF  DEXTRINE. 

THE  manufacture  of  dextrine  results  from  starch,  by 
the  heating  of  the  same  with  acids  or  with  diastase 
(malt  extract).  In  industry  the  term  dextrine  only 
signifies  starch  dextrine,  i.  e.,  such  preparations  as 
have  been  obtained  by  the  artificial  transformation  of 
starch,  containing  usually  besides  dextrine  also  un- 
changed starch,  soluble  starch,  glucose,  and  water  in 
considerable  quantities.  In  the  manufacture  of  dex- 
trine the  following  observations  are  of  the  greatest 
moment : — 

1.  The  roasting  of  starch  at  a  suitable  temperature. 

2.  The  heating  of  starch  with  diluted  acids  for  a 

short  time,  or 

3.  The  treatment  of  starch  with  a  solution  of  dias- 

tase in  a  temperature  ranging  between  60°  and 
70°  C.  (140°  and  158°  F.)  for  a  brief  period. 

These  are  the  conditions  for  obtaining  the  largest 
possible  quantity  of  dextrine  and  the  least  possible 
amount  of  starch-sugar.  For  the  industrial  produc- 
tion of  dextrine,  the  principal  point  in  view  is,  there- 
fore, that  on  the  one  hand  the  starch  is  transformed  as 
completely  as  possible  into  dextrine,  and  on  the  other 
hand,  that  the  sugar-formation  which  will  more  or 
less  ensue  is  possibly  prevented.  The  purity  and 


284  MANUFACTURE    OF    STARCH,    ETC. 

the  value  of  the  product  depend  above  all  on  the  obser- 
vation of  these  two  points.  Of  course  the  manufac- 
turer must,  as  is  self-evident^  pay  attention  that  the 
dextrine  is  produced  as  profitably  as  possible;  hence 
it  is  of  less  importance  to  furnish  a  chemically  pure 
article,  since  this  is  but  seldom  demanded  for  practical 
purposes.  The  obtaining  of  a  well  pasting  and  thick- 
ening article  is  what  is  most  desired. 

For  the  manufacture  of  dextrine  such  starch  is  ap- 
plied as  is  most  easily  attainable  at  the  place  of  its 
manufacture. 

The  production  of  dextrine  from  starch  is  performed 
in  three  different  ways,  to  wit : — 

1.  By  mere  roasting. 

2.  By  the  action  of  acids. 

8.  By  the  action  of  diastase. 

1.  THE  MANUFACTURE  OF  DEXTRINE  BY  THE 
ROASTING  OF  STARCH. 

When  dry  starch  is  heated  at  a  temperature  of  212° 
to  250°  C.  (413°.6  to  482°  F.),  and  is  for  some  time 
kept  in  this  temperature,  it  will,  according  to  the  same, 
be  transformed  into  one  of  the  following  shades  of 
color :  yellow,  brownish-yellow,  or  yellowish-brown, 
and  is  thus  changed  into  roast-gum  or  dextrine.  The 
process  of  manufacturing  roast-gum  is  very  simple. 
It  is  only  requisite  to  manage  the  operation  of  heating 
in  the  most  suitable  manner;  in  fact,  so  that  the  trans- 
formation of  the  starch  ensues  very  evenly,  and  as  com- 
pletely as  is  possible  at  the  designated  temperature. 
To  this  end  various  propositions  have  been  made. 

The  best  and  most  secure  way  of  regulating  the 
temperature  is  by  means  of  an  oil-bath.     A  flat  kettle, 


THE    TECHNOLOGY    OF    DEXTRIXE. 


285 


with  a  slightly  convex  bottom,  is  suspended  in  a  second 
somewhat  larger  kettle,  in  which  oil  is  contained,  so 
that  the  first  kettle  is  surrounded  by  the  oil.  A  ther- 
mometer, inserted  in  the  oil,  indicates  the  temperature. 
A  stirring-apparatus  of  metal,  touching  the  bottom  of 
the  inner  kettle,  and  by  which  the  starch  placed  therein 
can  be  turned,  gradually  causes  the  starch-granules  to 
come  in  contact  with  the  sides  of  the  kettle,  and  thus 
obtain  the  required  temperature  for  the  transformation 
of  the  starch  into  roast-gum. 

An  excellent  apparatus,  constructed  on  the  principle 
just  described,  is  delineated  by  Figs.  46,  47,  and  48. 

Fig.  46. 


Dextrine  roasting  apparatus.     (Ground  view.) 

This  dextrine  roasting  apparatus  consists  of  a  double 
cylinder  of  wrought-iron  plates,  which  is  supplied  with 
an  hermetical  closure,  easily  accessible  on  both  sides, 
and  a  well-constructed  stirring  appliance. 


286 


MANUFACTURE    OF    STARCH,    ETC, 


On  the  upper  part  of  the  cylinder  an  oval-formed 
hopper,  (?,  is  placed,  by  means  of  which  the  apparatus 
is  from  time  to  time  supplied  with  starch.  By  the  aid 
of  this  apparatus,  wheat-,  rice-,  or  potato-starch  can  be 

Fig.  47. 


Dextrine  roasting  apparatus.     (Lateral  section.) 

transformed  into  dextrine,  as  long  as  only  a  roast-gum 
in  powder  form  is  to  be  produced  ;  but  not  in  the  shape 
of  transparent  pieces  resembling  the  natural  gum. 
But  the  starch  must  of  course  previously  be  made 
entirely  free  from  its  17  per  cent,  of  water.  This  is 
done  by  drying  in  the  dry  ing -room,  F^  at  80°  C. 
(176°  F.). 

The  loss  of  weight  ensuing  afterwards  in  the  roast- 
ing apparatus  will  be  very  small.  It  maybe  generally 
accepted  that  100  kilogrammes  (220  Ibs.)  of  air-dry 
starch — in  the  form  as  it  is  obtained  from  the  starch 
manufactories  —  furnishes  on  an  average  80  kilo- 
grammes (176  Ibs.)  finished  roast-gum  of  a  good 
quality. 


THE    TECHNOLOGY    OF    DEXTRINE.  287 

By  means  of  this  apparatus  the  following  articles 
can  be  produced  from  starch : — 

Gommeline  (white  dextrine). 

Dextrine  (light-yellow  dextrine). 

Oommes  factice  (dark-yellow  dextrine). 

Leiogomme  (burnt  or  calcined  starch),  and  neutral 
white  yellowish  dextrine.  - 

From  wheat-starch : — 

Adrug  online  (white  dextrine). 

Gomme  ceriale  (yellowish  dextrine). 

Amidon-grille  (calcined  wheat-starch),  etc.  etc. 

By  means  of  this  apparatus  the  value  of  the  starch 
to  be  worked  up  into  dextrine  is  increased  20  per  cent, 
over  and  above  that  produced  by  any  other  mechanism. 

The  impelling  power  required  for  this  apparatus  is 
about  one-eighth  horse-power,  and  the  stirring  machine 
makes  eight  revolutions  per  minute. 

This  apparatus  is  applied  as  follows  : — 

The  double  casing  of  the  machinery  A  having  been 
filled  to  the  height  of  the  gauge-cock  with  well  refined 
rape-seed  oil,  a  fire  having  been  kindled  under  the  cy- 
linder, the  stirrer  is  put  in  motion,  and  the  apparatus 
is  filled  with  anhydrous  starch  (250  kilogrammes  = 
550  Ibs.),  by  means  of  the  hopper  c. 

The  oil  gradually  expanding  by  the  great  heat  that 
ensues  rises  noticeably,  so  that  in  a  very  short  time  the 
entire  inner  cylinder  will  be  surrounded  by  it.  Gradu- 
ally the  oil  enters  the  oval  barrel  A  (Fig.  48),  which, 
for  the  sake  of  security,  is  supplied  with  a  waste  pipe. 

Inasmuch  as  the  rape-seed  oil  is  a  poor  conductor  of 
heat,  and  hence  retains  the  once  acquired  temperature 
for  a  long  time,  a  moderate  fire  suffices  for  the  creation 
of  the  diverse  degrees  of  heat  requisite  for  producing 
the  various  kinds  of  roast-gum.  The  roast-gum  is  fin- 


288 


MANUFACTURE    OF    STARCH,    ETC. 


ished  as  soon  as  a  decided  smell  becomes  noticeable  near 
the  hopper,  and  the  emptying  of  the  apparatus  must  be 


05- 


ei- 


O- 


I 


C     03 

If 

o>    ~o 

u 


at  once  attended  to,  by^the  opening  of  one  of  the  front 
closures.  The  roast-gum  having  mostly  formed  in 
pieces  is  then  placed  in  the  metal  dish  B,  which  is 


THE    TECHNOLOGY    OF    DEXTRIXE.  289 

about  2.5  metres  (8.2  feet)  long,  and  1.2  metres  (3.94 
feet)  wide,  the  larger  pieces  being  crushed  and  sifted 
preparatory  to  pulverizing  the  same  in  the  crushing 
mill  D.  But  inasmuch  as  such  a  bruising  mill  does  not 
turn  out  the  roast-gum  quite  evenly,  it  is  also  placed  in 
a  sieve-drum,  or  in  the  gauge-cylinder  E,  and  is  then 
ready  for  packing. 

The  oil  in  the  casing  can  be  used  for  several  months, 
and  needs  only  to  be  replenished  occasionally  when  it 
becomes  thickened  by  decomposition.  For  the  roasting 
of  starch  large  cylinders  of  wrought  iron  are  also  some- 
times used,  similar  to  those  which  are  in  use  for  roast- 
ing coffee.  Instead  of  the  common  roasting  cylinders, 
which  have  to  be  periodically  filled  and  emptied,  a 
machine  consisting  of  a  cylindrical  roasting  apparatus 
which  can  be  constantly  kept  in  motion  is  often  applied. 
These  cylinders  are  usually  made  of  wrought  iron  of 
3.2  metres  (10.5  feet  length,  and  0.32  metre  (1.05  feet) 
diameter.  They  are  placed  in  an  inclined  position  over 
a  fire-place,  in  the  higher  end  of  which  the  starch  is  put 
in,  at  the  same  rate  as  from  the  lower  part  thereof  the 
roast-gum  is  emptied.  For  producing  the  darker  pro- 
duct the  first  article  is  passed  again  through  cylinders 
at  an  increased  heat.  Generally  several  cylinders  are 
placed  over  the  same  fire,  and  their  turning  is  managed 
by  cog-wheels.  In  the  large  establishment  of  Proud- 
foot  &  Co.,  in  Manchester,  England,  five  of  such  iron 
cylinders  of  3  metres  (9.84  feet)  length,  and  0.3  metre 
(0.98  foot)  diameter  are  placed  retort-like  alongside 
and  above  each  other  in  a  common  furnace,  and  as 
has  already  been  stated,  in  a  somewhat  inclined  posi- 
tion. In  this  factory  4000  kilogrammes  (8800  Ibs.)  of 
dextrine  are  produced  daily. 

A  very  simple  contrivance,  although  less  suitable 

19 


290 


MANUFACTURE    OF    STAKCH,    ETC. 


for  the  purpose  of  producing  dextrine,  is  the  apparatus 
constructed  by  Payen.  It  consists  of  a  furnace  with 
a  hot  blast  (Fig.  49),  which  permits  of  the  production 
of  an  even  and  sufficiently  high  temperature. 


.  49. 


Ceutimip  s 


iMeter. 


Furnace  for  the  production  of  starch-gum  according  to  Payen's  construction. 

The  upper  space  of  the  immured  furnace  serves  for 
the  reception  of  the  dry  starch,  which  is  divided  into 
layers  of  from  3  to  4  centimetres  (1.18  to  1.57  inches)  in 
height  in  light  boxes  made  of  brass  plate.  The  pro- 
cess of  roasting  is  performed  by  heated  air.  Of  course 
a  thermometer  must  indicate  the  temperature  of  the 
chamber.  The  heated  air  takes  up  the  heat  which  is 
imparted  to  the  walled-in  apparatus  and  circulates  in 
the  channels  as  represented  in  the  sketch  (Fig.  49), 
enters  into  the  furnace  by  J5,  spreads  out  therein,  heat- 
ing the  walls  and  the  starch,  and  returns  thereupon  by 


THE   TECHNOLOGY    OF    DEXTRINE.  291 

D  into  the  channels  to  become  again  heated  and  to 
traverse  over  the  same  space.  The  starch  thereby  again 
gradually  turns  yellowish-brown,  and  is  then  in  a  great 
measure  soluble  in  water,  and  is  transformed  into  roast- 
gum.  Of  course  the  heating-chamber  is  to  be  supplied 
with  iron  frames  for  the  insertion  of  a  corresponding 
number  of  boxes. 

Inasmuch  as  the  starch  contains  a  considerable 
amount  of  water,  the  process  of  roasting  must  needs 
be  preceded  by  a  corresponding  drying  of  the  starch. 
Thus  at  the  beginning  preparations  for  the  withdrawing 
of  the  moist  air  must  be  made.  For  this  purpose  an 
aperture  is  made  in  the  very  accurately  fitting  iron 
door,  which  is  afterwards  closed.  Prof.  Otto,  of  Bruns- 
wick, justly  remarks,  that  it  would  be  hardly  possible 
in  such  a  roasting  chamber  to  raise  the  temperature 
evenly  to  the  required  height,  nor  can  the  starch  while 
lying  on  the  iron  boxes  obtain  an  even  roasting,  inas- 
much as  it  is  not  turned  over. 

In  conclusion  may  yet  be  mentioned  Pochin  and 
Wooley^  patented  method  of  manufacturing  dextrine. 
The  completely  dried  (but  not  roasted)  wheat  or  po- 
tato-starch is  mixed  with  one-fourth  to  one-eighth 
weight  part  of  butter-milk  or  sour  milk,  sifted  through 
a  fine  wire  sieve  of  150  meshes  per  square  decimetre 
(decimetre  =  3.937  inches),  and  after  drying  again,  is 
roasted  at  a  gentle  heat  until  it  appears  yellowish  or 
brownish.  According  to  the  quantity  of  the  butter- 
milk applied,  the  dextrine  will  take  a  more  or  less 
light-yellow  color, and  thus  any  desired  shade  of  color 
can  be  attained. 


292  MANUFACTURE  OF  STARCH,  ETC. 

2.  THE  MANUFACTURE  OF  DEXTRINE  BY  THE 
APPLICATION  OF  AdDS. 

If  dry  starch  is  moistened  with  water,  to  which  a 
small  quantity  of  a  non-volatile  or  at  least  not  very 
volatile  acid  has  heen  added,  and  thereupon,  after  being 
previously  dried,  is  exposed  to  a  temperature  of  from 
100°  to  125°  C.  (212°  to  257°  F.),  it  will  transform 
into  dextrine.  Dextrine  obtained  in  this  manner,  is 
generally  of  a  lighter  color  than  the  leiogomrne,  which 
is  produced  by  simply  roasting  the  starch. 

The  production  of  dextrine  by  means  of  acids  is 
therefore  a  very  simple  aifair,  and  is  even  easier  to 
accomplish  than  the  manufacture  of  roast-gum,  since 
for  this  operation  a  less  high  temperature  is  required. 
But  by  this  method,  great  care  must  be  observed  that 
the  action  of  the  acids  is  arrested  as  soon  as  the  trans- 
formation of  the  starch  into  dextrine  has  been  com- 
pleted, which  can  be  proven  by  the  iodine  test.  As 
long  as  the  mass  yet  contains  unchanged  starch,  it  will 
be  colored  blue  by  the  application  of  iodine.  But 
whenever  the  reaction  of  iodine  ceases,  this  will  be  a 
sign  of  the  complete  transformation  of  the  starch.  The 
action  of  the  acid  must  at  once  be  interrupted  so  as 
to  prevent  a  considerable  part  of  the  formed  dextrine 
passing  over  into  sugar. 

In  order  to  prevent  the  formation  of  sugar  in  the 
process  of  manufacturing  dextrine,  or  at  least  to  limit 
the  same,  it  would  be  best  never  to  heat  the  starch 
with  acid  and  so  much  water,  that  the  forming  dextrine 
can  become  dissolved.  For  not  alone  in  this  case  does 
the  evaporation  of  the  liquid  mass  require  large  quan- 
tities of  fuel,  and  thereby  occasion  considerable  ex- 
pense, there  would  also  during  the  evaporation  of  the 


THE   TECHNOLOGY    OP   DEXTRINE.  293 

dextrine  solution  be  a  considerable  part  of  the  dextrine 
transformed  into  grape-sugar.  This  would  be  caused 
by  the  prolonged  adtion  of  the  acid  still  contained  in 
the  dextrine  solution.  In  practical  operation  the  starch, 
therefore,  is  mixed  with  the  necessary  quantity  of  dilute 
acid— based  on  experience — in  a  moist  powder,  and 
this  powder  is  exposed  to  a  suitable  temperature  (100° 
to  120°  C.  =212°  to  248°  F.)  until  a  complete  trans- 
formation of  the  starch  ensues.  Among  acids,  muri- 
atic and  nitric  are  the  ingredients  which  are  chiefly 
applied  for  the  making  of  dextrine.  The  acids  must 
above  all  .be  free  from  gaseous  chloride,  since  this 
otherwise  passes  over  into  the  formed  dextrine-  This 
would  cause  the  colors  which  are  prepared  with  such 
dextrine — for  paper  and  cloth  printing — to  lose  their 
intensity,  that  is  to  say,  they  would  be  bleached. 
Sulphuric  acid  does  not  often  find  application  in  the 
manufacture  of  dextrine,  but  is  still  sometimes  used 
for  preparing  liquid  dextrine.  Dextrine  obtained  by 
its  application  has  the  peculiarity  of  easily  becoming 
sticky,  and  even  does  not  entirely  lose  the  same  by 
drying  as  the  sulphuric  acid  is  but  slightly  volatile. 
Such  dextrine  is  also  generally  of  a  darker  color.  But, 
on  the  other  hand,  for  the  production  of  liquid  dextrine 
oxalic  acid  and  lactic  acid  are  frequently  used,  and 
their  excess  must  after  completion  of  the  transformation 
of  the  starch  into  dextrine  be  separated  or  neutralized 
by  means  of  carbonate  of  lime.  Thus  oxalate  of  lime 
is  formed,  which  does  not  cause  the  formation  of  sugar, 
during  the  evaporation  of  the  dextrine  solution. 

Fr.  Anthon  describes  a  new  method  of  manufactur- 
ing dextrine.  Hitherto  pure  starch  only  has  been 
applied  for  the  production  of  dextrine;  while  allow- 
ing the  loss  of  that  starch  during  the  process  of 


294  MANUFACTURE    OF    STARCH,    ETC. 

making  potato-starch  which  is  contained  in  the  starch 
fibres.  In  order  to  avoid  this  loss  the  entire  substance 
of  the  potato  can  be  applied.  The  potato  is  to  this  end 
previously  freed  of  its  soluble  ingredients  by  extraction 
with  acidulated  or  alkaline  water,  and  thereupon  dried 
and  milled  fine. 

Such  starch  is  as  usual  soured  with  hydrofluoric 
silicic  acid  in  the  ratio  of  from  five  to  ten  per  mille  of 
the  weight  of  the  starch.  This  acidulated  starch  is 
then  spread  in  the  drying-room  upon  linen  hurdles, 
and  dried  in  a  temperature  of  from  38°  to  44°  C.  (100.4° 
to  111.2°  P.)  so  long  until  it  no  longer  decreases  in 
weight.  The  temperature  is  then  raised  from  70°  to 
75°  C.  (158°  to  167°  F.),  and  it  is  also  left  in  this  tem- 
perature until  its  state  of  dryness  corresponds  there- 
with. Thereupon  the  temperature  is  increased  to  90°  C. 
(194°  P.),  and  it  is  thus  kept  for  half  an  hour,  and,  fin- 
ally, the  perfectly  dried  starch  is  put  while  yet  hot  into 
moulds  of  tin  plate  and  kept  therein  for  a  period  of 
from  one  to  two  hours  in  a  temperature  of  100°  to  125° 
C.  (212°  to  257°  P.),  until  the  dextrine  formation  is 
finished,  that  is,  when  a  sample  taken  therefrom,  after 
cooling  off  and  being  moistened  with  cold  water,  as- 
sumes a  nice,  glassy,  transparent,  globular  formation. 

The  apparatus  required  for  this  purpose,  designated 
as  the  dextrine  cellular  apparatus  (Fig.  50),  consists 
of  a  cubic-shaped  metal  boiler  (kettle)./ w  a  a  mf,  which 
serves  for  the  water- bath  (salt  lye,  or  eventually  also 
as  oil-bath),  and  which  can  be  heated  according  to  re- 
quirement to  from  90°  to  125°  C.  (194°  to  255°  P.). 
Inside  of  this  apparatus  are  inserted  flat  tin  cells  A  A7 
of  a  corresponding  height  and  width,  but  they  must 
not  exceed  the  diameter  of  25  millimetres  (0.984  inch) 
in  thickness.  They  are  designed  to  expose  the  acidy 


THE   TECHNOLOGY    OF    DEXTRINE.  295 

and  dried  starch  to  a  temperature  of  from  100°  to  125° 
C.  (212°  to  257°  F.)  until  the  dextrine  formation  is 
finished.  The  respective  cells  are  placed  in  the  kettle 
surrounded  by  the  bath  at  a  suitable  distance  from 


2  met. 
I 


Dextrine  cellular  apparatus  of  recent  construction. 

each  other,  and  after  the  process  is  finished,  taken 
out  to  be  emptied  and  refilled,  or  they  may  be  fastened 
in  the  kettle,  as  is  the  case  in  our  sketch.  In  this  event 
they  are  supplied  with  an  inclined  bottom. 

The  fireplace  for  heating  this  apparatus  is  to  be  so 
constructed  that  the  heat  can  be  turned  off  at  once,  in 
order  by  application  of  the  oil-bath  to  avoid  an  over- 
heating. The  outer  walls  of  the  apparatus  are  to  be 
lined  with  flannel  and  wood.  The  intermediate  bottom 
a  a  a  a  is  to  effect  a  rapid  circulation  of  the  liquid,  lye, 


296  MANUFACTURE    OF    STARCH,    ETC. 

or  oil.  The  pipe  H  serves  for  cooling  off  at  will  the 
cells  with  their  contents.  Through  this  pipe  a  cold 
liquid  can  be  conducted  into  the  kettle  at  any  time, 
but  of  course  only  after  draining  off  the  hot  lye  or  oil 
by  means  of  two  stopcocks  which  are  placed  on  the 
side  of  the  apparatus. 

As  is  obvious,  the  apparatus  above  is  supplied  with 
a  well-fitting  cover,  so  that  no  lye  or  oil  can  boil  over. 

The  following  is  a  receipt  for  producing  dextrine  by 
means  of  oxalic  acid :  500  weight  parts  of  potato- 
starch,*  1500  parts  water,  and  8  parts  of  oxalic  acid 
are  heated  in  a  water-bath,  until  the  tincture  of  iodine 
no  longer  colors  the  liquid  blue.  After  cooling  off,  the 
solution  is  neutralized  with  chalk,  permitting  it  to  rest 
for  several  days,  then  filtered  and  evaporated  to  the 
consistency  of  dough.  This  mass  is  finally  slowly  and 
perfectly  dried. 

3.  THE  MANUFACTURE  OF  DEXTRINE  BY  MEANS 
OF  DIASTASE. 

Ere  yet  the  simple  process  of  manufacturing  dex- 
trine, now  in  vogue,  was  known,  dextrine  already  ex- 
isted as  a  commercial  commodity,  but  it  had  quite  a 
different  appearance,  and  was  produced  in  a  different 
manner.  A  solution  of  malt,  starch,  and  the  requisite 
quantity  of  water  was  heated  at  a  high  mashing  tem- 
perature, 75°  C.  (167°  F.),  and  finally  brought  to  a  boil, 
and  after  filtering,  it  was  evaporated  to  the  consistency 
of  a  thick  syrup,  and  this  mass  was  dried  out.  The 
substance  thus  obtained  was  similar  to  gum-arabic. 

*  Corn-sttirch  will  answer  the  same  purpose,  providing  the  quan- 
tity of  the  acid  is  somewhat  increased. 


THE    TECHNOLOGY    OF    DEXTRINE.  297 

It  was  a  mixture  of  starch-gum  and    sugar,   but   it 
passed  in  commerce  as  dextrine  or  starch-gum. 

The  making  of  dextrine  by  means  of  diastase  is  no 
longer  in  use,  but  nevertheless  we  will  briefly  describe 
this  method. 

For  the  production  of  dextrine  by  the  action  of  dias- 
tase on  starch,  an  extract  of  "germinated  barley"  (malt 
extract)  or  finely  ground  malt  is  applied,  the  diastase 
thereof  being  of  greatest  effect  at  a  temperature  of 
from  65°  to  75°  C.  (149°  to  167°  F.).  At  a  lower  tem- 
perature the  formation  of  dextrine  ensues  but  slowly, 
and  in  an  increased  heat  it  ceases  entirely.  As  soon  as 
the  transformation  of  the  starch  into  dextrine  is  effected, 
the  mass  composed  of  dextrine  malt  and  water,  is  im- 
mediately boiled,  whereby  a  further  transformation  of 
dextrine  into  sugar  need  no  longer  be  feared.  Never- 
theless,  the  dextrine  obtained  in  this  way  will  never  be 
entirely  free  from  sugar.  However,  the  sugar  con- 
tained in  dextrine  is  for  many  purposes  even  desirable, 
and  for  this  purpose  such  a  product  is  prepared  by 
some  French  manufacturers  intentionally.  It  is  intro- 
duced into  the  traffic  as  dextrine-sucree  (dextrine- 
sugar). 

This  method  of  manipulation  is  therefore  much  more 
simple  than  those  heretofore  described,  but  its  general 
introduction  is  hindered  by  great  obstacles.  These  are: 

1,  the  large  amount  of  water  contained  in  such  dextrine 
(dextrine  syrup)  makes   the  transportation  difficult; 

2,  by  the  application  of  malt,  as  has  been  heretofore 
elucidated,  it  is  unavoidable  that  a  part  of  the  starch 
be  transformed  into  sugar,  and  by  these  admixtures 
the  dextrine  syrup  loses  a  great  amount  of  its  dura- 
bility, and  aided   by  the  non-separated  parts  of  the 
gluten  of  the  malt  becomes  very  easily  fermentable. 


298 


MANUFACTURE    OF    STARCH,    ETC. 


Payen  has  constructed  an  apparatus  for  the  produc- 
tion of  dextrine  with  diastase  (Fig.  51). 

For  the  manufacture  of  dextrine  by  this  method,  the 
copper  boiler,  c,  is  suspended  in  a  wooden  vat,  a,  half 
filled  with  water.  The  vat  as  well  as  the  inserted 
boiler  is  connected  with  steam-pipes,  in  which  nume- 


Payen's  apparatus  for  the  production  of  dextrine  with  diastase. 

rous  openings  admit  the  steam  as  it  may  be  required. 
To  accomplish  this,  the  stopcocks  d  and  a'  need  only  be 
opened.  The  inner  boiler  is  filled  with  cold  water,  and 
in  this  the  coarsely  ground  malt  is  placed.  The  steam- 
cock  a'  is  then  opened,  and  steam  is  permitted  to  stream 
in,  until  the  water  in  the  outside  tank  gradually  reaches 
a  temperature  of  from  60°  to  70°  C.  (140°  to  158°  F.). 
This  temperature  is  maintained  constant  by  means  of 


THE    TECHNOLOGY    OP    DEXTRINE.  299 

slowly  admitting  more  steam.  This  heat  is  imparted 
to  the  malt  decoction,  and  it  raises  this  also  to  70°  C. 
(158°  F.),  a  temperature  most  suitable  for  the  forma- 
tion of  dextrine.  The  diastase  changes  in  the  first 
place  the  starch  of  the  malt  itself,  but  in  order  to 
exhaust  its  effect  more  starch  is  added,  as  long  as  this 
will  yet  be  dissolved.  Payen  and  Persoz  recommend 
for  this  purpose  the  mixing  of  from  6  to  10  weight 
parts  of  bruised  malt  with  400  parts  of  water,  to  in- 
crease the  temperature  to  70°  C.  (158°  F.),  and  to  add 
to  this  mixture  100  weight  parts  of  starch.  It  is  best 
to  take  potato-starch.  The  temperature  is  thereupon 
gradually  raised  to  75°  C.  (167°  F.),  and  while  stirring 
the  mixture  is  kept  at  this  temperature,  until  it  becomes 
a  clear  and  thin  liquid.  This  usually  requires  a  period 
of  half  an  hour.  After  the  starch  is  liquefied,  the  tem- 
perature must  be  quickly  increased  to  from  95°  to  100° 
C.  (203°  to  212°  F.),  and  the  mass  be  kept  boiling  for 
several  minutes.  Of  the  sufficient  transformation  of 
the  starch  into  dextrine,  and  starch-sugar  (glucose), 
the  application  of  the  iodine  solution  will  convince,  by 
taking  out  of  the  copper  boiler,  c,  from  one  to  two 
drops  of  the  liquid  and  mixing  it  with  a  drop  of  an 
aqueous  iodine  solution.  As  long  as  a  blue  coloring 
ensues,  the  mass  in  the  boiler  still  contains  undecom- 
posed  starch  ;  but  if  the  liquid  is  colored  a  "burgundy 
red,"  this  may  be  accepted  as  a  proof  of  the  complete 
transformation  of  the  starch.  The  further  action  of 
the  diastase  on  the  formed  dextrine  is  then  to  be  inter- 
rupted, by  opening  the  steam-cock,  c,  entirely ;  and  by 
causing  the  mass  to  boil  quickly.  If  the  action  of  the 
diastase  had  not  been  caused  to  cease,  a  product  too 
rich  in  sugar  would  have  been  the  result. 

As  soon  as  the  liquid  has  been  caused  to  boil,  and 


300  MANUFACTURE    OF    STAKCH,    ETC. 

the  action  of  the  diastase  is  thus  destroyed,  the  boiling 
liquid  is  permitted  to  flow,  by  opening  the  cock,  through 
the  filter  &,  and  from  thence  into  the  reservoir  k.  The 
further  concentration  ensues  in  the  apparatus  d.  in 
whose  horizontal  kettle  a  long  worm-pipe,  de,  is  affixed. 
The  exhaust-steam  of  the  engine  enters  at  if,  the  pipe 
itself  rests  in  a  box,  g  and  *f,  and  is  kept  in  motion  by 
a  pully  nearj£  The  boiler  is  filled  to  about  one-half  of 
its  capacity  with  the  liquid  from  the  reservoir  fc,  into 
which  the  steam- worm  is  inserted.  This  maintains  it 
in  constant  motion,  and  lifts  by  every  revolution  parts 
of  the  liquid  to  the  surface,  and  the  water  is  quickly 
turned  into  steam.  To  increase  the  evaporation,  a 
blower,  m,  drives  a  brisk  stream  of  air  across  the  boil- 
ing liquid,  and  drives  the  forming  vapors  in  the  direc- 
tion of  the  dart  through  the  chimney  into  the  open  air. 

The  concentration  of  the  liquid  is  carried  on  so  far, 
that  it  forms  such  a  refractory  mass  when  cooled  off, 
that  the  hydrometer  no  longer  sinks ;  hence  its  tech- 
nical appellation,  "  imponderable  syrup." 

This  dextrine  is  frequently  applied  by  brewers  in 
France.  The  syrup  which  is  not  colorless  is  neverthe- 
less suitable  for  this  sort  of  application,  since  the  color 
does  no  harm. 

Experiments  for  producing  Dextrine  from  Wood. — As 
early  as  1820,  Bracannot  tried  to  produce  dextrine  from 
the  fibre  of  wood,  but  without  any  particular  success. 
But  Vogel,  Bertholet,  and,  later,  Anilion,  accomplished 
this  object  with  far  better  results;  but  all  endeavors 
for  the  solution  of  this  highly  important  matter,  for 
practical  purposes,  have  thus  far  resulted  in  but  little 
of  importance,  and  it  will  therefore  be  sufficient  merely 
to  explain  here  a  series  of  experiments,  made  by  An- 
thon,  with  a  view  to  transform  wood  into  dextrine. 


THE    TECHNOLOGY    OF    DEXTRINE.  301 

Three  small  pasteboard-like  pieces  of  white  air-dry 
paper,  called  "  stuff"  by  the  paper  manufacturers — 
each  of  these  pieces  weighing  1.28  grammes  (19.75 
grains) — were  dried  in  a  temperature  of  87.°5  C.  (189°.5 
F.),  whereby  the  weight  of  each  was  reduced  to  1.17 
grammes  (18.05  grains).  These  were  then  at  once 
saturated  in  diluted  muriatic  acid,  and  thus: — 

a,  with  120-fold  diluted  muriatic  acid  of  16°  B. 

6,      "      90         "  "  "  " 

c,      "      60         "  "  "  " 

left  for  a  period  of  four  hours. 

After  the  lapse  of  this  time  the  "stuff"  was  with- 
drawn from  the  muriatic  acid,  and  the  acid  permitted 
to  drip  off,  and  the  stuff1  was  then  re  weighed.  The 
weight  of 

a,  was-  then  3.36  grammes  (51.84  grains). 
6,         "         3.37         "         (52  tl      ). 

c,         "         3.36         "         (51.84       "      ). 

The  "stuff"  therefore  had  absorbed  double  of  its  origi- 
nal weight  of  muriatic  acid,  and  was  then  spread  on  a 
glass  plate,  completely  dried  out  to  1.75  grammes  (27 
grains),  and  heated  in  glass  tubes  over  a  salt  bath  to 
a  temperature  of  112°.5  C.  (234°.5  F.)  and  kept  in  this 
temperature  for  three  hours. 

These  three  samples  appeared  to  be  of  a  dirty  yel- 
lowish color,  and  each  of  them  weighed  1.32  grammes 
(20.36  grains).  Wet  with  cold  water,  the  yellow  color 
became  much  plainer,  and  soon  appeared  light  brown, 
a  but  little,  b  more  so,  and  c  most. 

AVhen  sprinkled  over  with  water,  none  of  the  three 
samples  appeared  like  dextrine,  because  it  was  neither 
mucilaginous,  nor  even  transparent.  Heated  in  water 


302  MANUFACTURE    OF    STARCH,    ETC. 

to  a  boil,  the  pasteboards,  resembling  strips,  retained 
their  shape  unaltered.  Perfectly  dried,  they  weighed 

a,     1.066  grammes         (16.45  grains), 
ft,     1.051         "  (16.22      u      ), 

c,     1.051         "  (16.22      "      ), 

and  hence  they  had  imparted  to  the  water  but  9.4  per 
cent,  of  soluble  matter,  notwithstanding  the  fact  that 
one  part  thereof  may  have  been  composed  of  clayey 
substances. 

From  this  series  of  experiments  it  becomes  therefore 
evident  that  muriatic  acid  in  respectively  190,  90,  and 
60-fold  dilution,  and  applied  as  stated  at  a  temperature 
of  112°  C.  (233°.6  F.),  acts  but  very  imperfectly  on 
wood  fibre,  so  that  at  best  but  9.4  per  cent,  of  this 
fibre  thereby  becomes  soluble. 

In  a  similar  manner  a  great  number  of  other  experi- 
ments of  this  kind  have  been  conducted  by  many 
modern  chemists,  but  thus  far  without  attaining  any 
practical  result. 

Manufacture  of  Chemically  Pure  Dextrine. — All  the 
methods  of  producing  dextrine,  as  hitherto  described, 
furnish  an  article  which  for  all  industrial  purposes  is 
sufficiently  pure  and  perfectly  applicable,  although  it 
still  contains  starch  not  quite  converted  and  burnt 
parts  of  the  same,  and  also  grape-sugar  in  more  or  less 
considerable  quantities. 

But  in  practice  sometimes  chemically  pure  dextrine 
is  needed,  which  can  be  best  obtained  by  the  process  of 
refining  the  common  commercial  dextrine. 

If  chemically  pure  dextrine  is  to  be  produced,  the 
aqueous  solution  of  commercial  dextrine  is  first  to  be 
discolored  by  boneblack,  and  after  filtering  and  concen- 
trating the  same  by  evaporation,  it  is  mixed  with  abso- 
lute alcohol.  The  alcohol  effects  the  separation  of  the 


THE    TECHXOLOGY    OF    DEXTRINE.  303 

sugar  from  the  dextrine,  while  the  sugar  remains 
soluble  in  the  liquid;  the  dextrine  being  insoluble  in 
alcohol  separates  in  the  form  of  a  flocculent  precipitate. 
This  precipitate  is  filtered  off,  dissolved  in  water,  again 
mixed  with  alcohol,  until  the  ensuing  precipitation  no 
longer  increases.  The  flaky,  separated  dextrine  is 
washed  over  a  filter  with  alcohol  in  order  to  eject  the 
last  traces  of  sugar.  But  in  this  condition  the  dextrine 
is  not  yet  perfectly  pure,  and  it  is  for  this  reason  again 
dissolved  in  water  and  precipitated  in  alcohol,  and  the 
filtrate  again  washed  out;  and  this  alternately  dis- 
solving in  water  and  precipitating  with  alcohol  is  re- 
peated so  long  until  a  sample  of  the  last  remaining 
dextrine,  when  dissolved  in  water  and  mixed  with  an 
alkaline  solution  of  oxide  of  copper  and  heated,  no 
longer  forms  a  red  precipitate  of  peroxide  of  copper. 

According  to  Payen  this  operation,  namely,  the 
alternate  solution  of  dextrine  in  water  and  precipitation 
with  alcohol,  must  be  repeated  at  least  ten  times  in 
order  to  obtain  chemically  pure  dextrine. 

Barford  obtained  by  this  method  from  a  commercial 
dextrine  produced  by  roasting,  by  means  of  a  12- fold 
solution  and  precipitation  by  means  of  alcohol,  a  per- 
fectly pure  dextrine;  while  dextrine  manufactured  by 
the  action  of  diastase  only  furnished  a  chemically  pure 
product  by  first  precipitating  the  sulphuric  acid  and 
phosphoric  acid,  originating  in  this  dextrine  from  the 
malt,  by  the  aid  of  sugar  of  lead.  The  formed  pre- 
cipitate was  filtered  off,  the  filtrate  saturated  with 
hydro-sulphurous  acid,  the  ensuing  sulphite  of  lead 
again  filtered  off,  and  the  solution  thus  obtained  re- 
peatedly treated  with  alcohol  as  previously  described. 


304  MANUFACTURE  OF  STARCH,  ETC. 

QUALITY  OF  DEXTRINE;  TESTING  OF  DEXTRINE  AS 
TO  ITS  CONTENTS  OF  IMPURITIES  AND  ADULTERA- 
TIONS. 

The  dextrine  of  commerce  forms  mostly  a  white  or 
pale-yellow  colored  powder,  which  is  of  more  or  less 
fineness.  When  bruised  by  squeezing  between  the 
fingers  it  does  not  grit,  is  tasteless,  possessing  a  faint 
but  very  specific  smell,  and  when  exposed  to  damp  air 
soon  becomes  moist.  Sometimes  it  appears  similar  to 
gum-arabic  in  pale,  yellowish  or  brown-yellowish,  irre- 
gular-shaped pieces  of  various  sizes  being  more  or  less 
lustrous.  Formerly  dextrine  was  introduced  into  com- 
merce exclusively  in  a  pulverized  form;  within  the  last 
decade  it  has  been  manufactured  on  an  extensive  scale 
in  lumps.  The  reason  for  this  seems  to  have  been  to  give 
to  this  important  product  a  more  extensive  application 
for  those  purposes  of  industry  for  which  hitherto  only 
the  Arabian  gum  and  and  the  Senegal  gum  have  been 
applied.  By  imparting  to  dextrine  the  form  and  ap- 
pearance of  gum-arabic,  the  prejudices  which  were 
heretofore  an  obstacle  to  its  use  in  lieu  of  the  natural 
gum  were  thus  easier  removed,  so  that  this  valuable 
product  enjoys  to-day  the  most  wide-spread  propaga- 
tion and  application.  It  is  furthermore  noteworthy, 
that  dextrine  in  pieces  is  preferable  to  that  furnished 
in  a  pulverized  form,  because  it  does  not  ball  together 
as  the  latter  does  when  saturated  with  water,  and  hence 
is  more  readily  soluble. 

Dextrine  appears  also  in  commerce  in  a  third  form 
— as  dextrine-syrup.  This  is  a  more  or  less  pale-yel- 
lowish, transparent,  tough,  and  glutinous  mass. 

Pure  dextrine  dissolves  in  water  completely,  leaving 
no  residuary  matter  when  burned,  its  solution  reacting 


THE    TECHNOLOGY    OF    DEXTKINE.  305 

neutral,  being  colored  by  iodine  tincture  not  blue  but 
red;  and  being  .insoluble  in  baryta  water  and  tannic 
acid.  From  the  alkaline  copper  solution  of  Fehling  it 
reduces  the  peroxide  of  copper  only  after  a  long  boil- 
ing, and  finally  does  not  discolor  an  alkaline  solution 
of  ferrocyanide  of  potash  when  being  heated. 

Since  the  dextrine  of  commerce  never  appears  per- 
fectly pure,  and  besides  its  contents  of  starch  and 
grape-sugar  it  also  frequently  holds  foreign  admixtures 
(sand,  heavy  spar,  gypsum),  and  even  injurious  sub- 
stances resulting  from  the  different  processes  of  pre- 
paration, such  as  mineral  and  organic  acids,  it  becomes 
in  most  cases  imperative  to  submit  the  dextrine,  prior 
to  its  application,  to  an  accurate  test. 

The  percentage  composition  of  the  commercial  dex- 
trine manufactured  for  industrial  purposes  can  be  seen 
from  the  table  of  analyses  annexed  : — 

Dextrine.          Sugar.          Insoluble  Water, 

substances. 

Prime  dextrine     .  .  .  12.45  8.77  13.14  5.64 

Dark  roasted  starch  .  70.43  1.92  19.97  7.68 

Brown  dextrine    .  .  63.60  7.67  14.51  14.23 

Gommeline  .         .  .  59.71  5.76  20.64  13.89 

Older  dextrine      .  .  49.78  1.42  30.80  1800 

Light  roasted  starch  .  5.34  0.24  86.47  7.95 

The  contents  of  starch-sugar  in  dextrine  are  proved 
as  follows  :  The  aqueous  solution  of  the  dextrine  to  be 
tested  is  mixed  and  boiled  with  a  solution  of  acetic 
oxide  of  copper.  If  starch-sugar  is  present,  red  per- 
oxide of  copper  will  separate  in  a  very  short  time.  The 
solution  of  dextrine  decomposes  the  acetic  oxide  of 
copper,  just  as  little  as  cane-sugar,  gum-solution,  or 
diluted  milk-sugar  solution,  while  the  least  quantity 
of  grape-sugar  will  readily  reduce  it. 

The   difference   between   dextrine    and   gum-arabic 

20 


306  MANUFACTURE   OF   STAKCH,   ETC. 

proves  itself  by  the  chemical  action  of  these  substances. 
The  gum-arabic  never  contains  in  natural  pieces  any 
traces  of  grape-sugar,  while  the  dextrine  of  commerce 
is  never  entirely  free  therefrom;  hence,  even  the  pro- 
duct designated  as  u  starch-sugar  free  dextrine,"  will 
reduce  an  alkaline  copper  oxide  solution  at  a  heat  of 
80°  C.  (176°  F.).  The  solution  of  gum-arabic  is  ren- 
dered turbid  and  white  by  a  solution  of  oxalic  acid, 
while  a  solution  of  dextrine  is  not  affected  thereby,  or 
at  least  very  little.  A  concentrated  solution  of  gum- 
arabic  produces,  with  mixtures  of  sesquioxide  of  iron, 
a  gelatinous  substance,  while  the  solution  of  dextrine 
never  does.  Arabian  gum,  when  heated  with  concen- 
trated nitric  acid  furnishes,  after  the  cooling  off  of  the 
solution,  mucic  acid,  which  separates,  while  dextrine  is 
thereby  transformed  into  soluble  oxalic  acid 

If  the  point  in  question  depends  on  the  quantitative 
determination  of  the  ingredients  contained  in  commer- 
cial dextrine,  which  are  soluble  in  water  (pure  dextrine 
and  grape-sugar),  such  can  be  best  accomplished,  as 
follows: — 

In  the  first  place  the  contents  of  water  are  to  be  de- 
termined. To  this  end  a  weighed  quantity  of  about  2 
to  3  grammes  (30.86  to  46.29  grains)  of  dextrine  is  to 
be  heated  in  a  drying-pipe  (shaped  like  the  letter  U) 
in  an  oil-bath,  at  a  temperature  of  110°  C.  (230°  F.), 
until  it  no  longer  suffers  a  reduction  in  weight.  During 
the  process  of  drying,  a  perfectly  dry  stream  of  air 
previously  passed  through  a  quantity  of  sulphuric  acid 
is  driven  into  the  drying-pipe,  U,  and  leaves  the  pipe 
ladened  with  moisture,  and  in  this  manner  the  drying 
of  the  dextrine  is  quickly  accomplished.  From  the 
loss  of  weight  of  the  weighed-off  quantity  of  dextrine, 
its  contents  of  water  can  be  accurately  calculated.  For 


THE   TECHNOLOGY    OF    DEXTRINE.  307 

the  determination  of  the  soluble  ingredients  contained 
in  the  air-dried  dextrine,  50  grammes  (771.50  grains)  are 
weighed  off,  and  mixed  in  500  grammes  (7715  grains)  of 
pure  distilled  water.  The  mixture  is  filtered,  an  accu- 
rately weighed-off  part  of  the  filtrate  is  again  evaporated 
and  dried  in  a  drying-tube  in  an  oil-bath,  at  110°  C« 
(230°  F.),  permitting  a  stream  of  air  to  pass  through 
sulphuric  acid,  and  from  thence  to  the  drying-tube. 
From  the  weight  of  the  perfectly  dry  residuum,  the 
quantity  of  the  previously  dissolved  ingredients  can  be 
calculated. 

In  case  the  contents  of  sugar  are  to  be  determined 
as  to  their  quantity,  besides  the  amount  of  soluble  in- 
gredients, Fehling's  alkaline  solution  of  copper  will  be 
best  suited.  10  cubic  centimetres  (2.70  fluidrachms) 
of  this  solution  are  reduced  by  0.05  gramme  (0.77 
grain)  of  starch-sugar. 

Of  the  filtered  solution  of  dextrine,  mentioned 
before,  so  much  is  dropped  into  Fehl ing's  copper  solu- 
tion, until  the  blue  color  of  the  mixture  entirely  disap- 
pears, that  is,  until  all  the  soluble  copper  is  precipitated 
as  red  peroxide  of  copper.  From  the  quantity  of  the 
solution  of  dextrine  used,  the  contents  of  sugar  can 
easily  be  calculated. 

Another  method  of  determining  the  amount  of  flour, 
starch,  and  other  adulterations  mixed  in  the  dextrine, 
is  by  means  of  the  action  of  iodine  vapors.  By  this 
treatment  the  following  shades  of  color  will  be  observed 
to  appear:  Roasted  starch  furnishes  according  to  the 
degree  of  its  roasting  a  violet,  similar  to  that  produced 
of  white  starch,  or  perhaps  a  reddish  violet.  Gom- 
meline  turns  pale  blue.  Leiogomme,  or  roasted  potato- 
starch,  furnishes  a  brownish  violet.  Dextrine  renders, 
according  to  its  method  of  manufacture,  various  shades 


308  MANUFACTURE    OF    STARCH,    ETC. 

of  color.  When  dextrine  is  produced  by  means  of  aqua 
regia  (nitric  and  muriatic  acid  mixed),  it  contains  much 
sugar,  and  in  this  case  only  colors  pale  red  brown. 
When  prepared  by  means  of  a  less  potent  acid,  a 
beautiful  violet  ensues. 

By  this  process  of  treatment,  the  nature  and  the 
properties  of  the  dextrine  can  be  tolerably  well  ascer- 
tained. 

In  conclusion,  we  recommend,  also,  the  following 
dyer's  experiments,  as  simple  means  for  determining 
the  quality  of  dextrine  : — 

1.  Print  an  entire  woollen  cloth  with  the  following 
color,  having  previously  passed   it  through  a  silken 
sieve,  steam  the  cloth,  and  after  this  wash  it  out. 

1  litre  (2.1  pints)  of  a  decoction  of  ammoniated 
cochineal,  prepared  with  30  grammes  (462.9  grains) 
of  cochineal  per  litre  (2.1  pints)  of  water  ; 

24  grammes  (370.32  grains)  of  powdered  alum; 

16  grammes  (247  grains)  of  oxalic  acid;  and 

375  grammes  (5786  grains)  dextrine  (gum)  powder. 

If  the  steam  color  obtained  is  a  beautiful,  delicate 
pink,  without  any  yellowish  tinge,  the  dextrine  may 
be  pronounced  as  being  superb. 

2.  The  dextrine  will  touch  the  mordants  all  the  more, 
the  more  aciduous  it  is.     For  this  test  the  following 
light  madder  pink  printing  color  is  applied  : — 

-g1^  litre  (1.05  fluidounce)  of  sulphate  of  clay  and  pot- 
ash (prepared  with  36.5  grammes  (563  grains)  of  alum 
per  litre  of  water). 

Y$  litre  of  water  (=  0.98  pts.),  and 

250  grammes  (8.75  oz.  av.)  of  pulverized  dextrine 
are  boiled,  and  then  stirred  until  completely  cooled  off. 

When  a  piece  of  calico  is  dipped  into  this  solution, 
it  is  left  exposed  to  the  air  for  twelve  hours.  After 


THE    TECHNOLOGY    OF    DEXTRIXE.  309 

that,  such  of  the  thickening  substance  and  of  the  mor- 
dant which  are  not  adherent  to  it  are  removed,  the 
calico  dyed  in  madder  and  soaped.  A  beautiful  very 
lively  pink  will  be  the  result,  while  if  the  gum  is  sour, 
sometimes  nothing  of  the  dye  will  remain  on  the  cloth. 

APPLICATION  OF  DEXTRINE. 

The  uses  of  dextrine  are  very  manifold,  and  its 
application  in  our  technical  industries  constantly  in- 
creases, it  being  an  inexpensive  substitute  for  the  im- 
ported Senegal  and  Arabic  gums.  It  is  applied  in  the 
art  of  printing  cloth  for  thickening  and  for  preparing 
mordants  for  fast  colors;  furthermore  for  the  thicken- 
ing of  several  caustic  colors,  "resists"  and  "reserves," 
also  for  caustic  dyes  and  for  some  "topical  colors"  on 
wool,  cotton,  and  silk,  as  well  as  generally  for  the  finish- 
ing and  stiffening  of  textiles.  For  the  printing  of 
calicoes  the  leiogomme  is  even  preferred  in  lieu  of  gum- 
arabic,  since  independent  of  its  being  less  expensive, 
this  dextrine  has  the  other  advantage  over  the  natural 
gum  of  not  curdling  so  easily  with  the  dyes  generally 
used  for  cloth  printing,  as  is  the  case  when  gum-arabic 
is  used.  Leiogomme  is  usualty  applied  in  calico-print- 
ing establishments  without  any  other  admixture.  Lev- 
eridge,  of  Massachusetts,  recently  took  out  letters 
patent  for  his  method  of  preparing  artificial  gum. 
This  article  has  been  introduced  in  several  calico 
manufactories  of  New  England,  and  its  preparation 
is  compounded  in  the  following  manner,  viz. : — 

40  parts  of  sago,  55  parts  of  potato-starch,  and  5 
parts  of  caustic  lime  (finely  powdered)  are  exposed  in 
open  vessels  to  a  temperature  not  exceeding  102°  C. 
(=  215.6°  F.),  until  the  mixture  is  entirely  dry  and 

20* 


310  MANUFACTURE    OF    STARCH,    ETC. 

appears  slightly  colored.  Thereupon  the  mass  is  to  be 
heated  in  a  closed  vessel  for  the  period  of  four  hours, 
in  a  temperature  of  162°  C.  (=323.6  F.).  The  mixture 
has  a  dark-brown  color,  and  is,  after  cooling  off,  finely 
powdered. 

In  the  paper-maker's  art  dextrine  serves  for  the  pro- 
duction of  colored  and  tinted  papers,  for  the  glazing  of 
cards  and  paper,  and  also  for  gumming  envelopes,  and 
postage  and  revenue  stamps.  It  is  also  used  for  the 
production  of  pastil  and  gouache  paintings,  and  for 
the  manufacture  of  inks.  From  dextrine  printing 
rollers  and  bearers  are  made;  also  the  so-called  "  chain- 
dressing"  for  weavers'  use,  and  sometimes  it  is  used  for 
lip-glue.  In  surgery  dextrine  serves  as  a  component 
part  in  the  preparation  of  solid  bandages  to  be  used  for 
dressing  fractures,  and  it  also  makes  an  excellent  court- 
plaster.  In  pharmacy  it  serves  as  an  admixture  with 
the  extracts  of  plants  in  order  to  make  them  applicable 
for  being  administered  in  powder  form.  For  domestic 
purposes  it  is  used  in  the  preparation  of  bread.  From 
33  to  45  per  cent,  of  dextrine  can  be  baked  with  the 
bread  without  such  being  noticed  by  the  consumer. 
The  bread  rises  well  and  keeps  fresh  for  a  long  time. 
It  is  likewise  used  for  preparing  fine  pastry.  In  bak- 
ing bread,  the  dextrine  forms  on  its  surface,  in  part  as 
the  crust  of  the  bread.  It  furthermore  forms  a  neces- 
sary ingredient  in  the  brewing  of  beer. 

The  dextrine  intended  for  cloth-printing  is  frequently 
manufactured  from  inferior  glutinous-starch  by  roast- 
ing, and  as  the  gluten  thereby  becomes  hard  and 
changes  into  a  burnt  mass  which  is  insoluble  in  water, 
the  dextrine  thus  made  impure  becomes  useless  as  a 
means  for  thickening.  The  burnt  gluten  easily  clogs 
or  fills  up  the  engraving  of  the  cylinders  in  roller- 


THE    TECHNOLOGY    OP    DEXTRIXE.  311 

printing,  and  causes  the  gumlike  printing  color  to  be- 
come so  tough  that  no  sharp  impression  can  be  obtained. 
In  order  to  remove  these  defects  the  following  manip- 
ulation is  recommended,  by  means  of  which  the  com- 
mercial dextrine  may  be  tested  at  once,  without  diffi- 
culty, with  regard  to  its  contents  of  burnt  gluten. 

According  to  the  recipe,  prepared  by  Bremei^  one  part 
of  the  dextrine  to  be  tested  is  mixed  with  one  part  of 
water  of  60°  C.  (140°  F.).  The  solution  thus  obtained 
is  again  mixed  in  five  parts  of  water  of  the  same  tem- 
perature. This  preparation  is  left  at  rest,  undisturbed 
for  twenty-four  hours,  during  which  time  the  burnt 
gluten  puffs  up,  without  dissolving  or  even  thickening 
the  liquid,  and  deposits  on  the  bottom.  The  greater 
the  contents  of  burnt  gluten  in  either  dextrine  or  leio- 
gomme  the  less  suitable  are  they  for  application  as  a 
means  for  thickening  or  weighting  textile  fabrics. 

Plan  for  Hie  Establishment  of  a  Potato-starch  and 
Dextrine  Manufactory. — In  Fig.  52  is  delineated  a 
sketch  of  an  establishment  both  for  starch  and  dextrine 
manufacturing.  This  sketch  represents  the  latest  im- 
provements and  inventions  in  this  branch  of  industry. 
The  arrangement  of  the  plan  is  visible  from  the  sketch, 
and  hence  but  little  remains  to  be  elucidated. 

This  potato-starch  and  dextrine  manufactory  having 
all  the  arrangements  and  machinery  for  the  manipula- 
tion of  from  15,000  to  20,000  kilogrammes  (33,000  to 
44,000  Ibs.)  of  potatoes  per  day,  consists  of  the  follow- 
ing different  parts,  which  are  all  arranged  in  the  most 
suitable  manner : — 

1,  A  spacious  vaulted  cellar  for  receiving  and  storing 
away  from  150,000  to  200,000  kilogrammes  (330,000  to 
440,000  Ibs.)  of  potatoes;  2,  hall  for  machinery  and 


312 


MANUFACTURE    OF    STARCH,    ETC. 


4i 

—  ,  '     ',  ,  •;,/.  ,.. 

c 

jt 

«?> 

«x                  "', 

^  s 

*o     ^> 

1 

"1  ; 

THE    TECHNOLOGY    OF    DEXTRINE.  313 


apparatus;  3,  boiler-house;  4,  engine-house;  5,  work- 
shop for  repairs;  6,  room  for  the  "  sedimenteurs " 
(settling  tanks);  7,  room  for  the  laveurs;  8,  room  for 
the  centrifugal-machine;  9,  room  for  producing  the 
leiogomme;  10,  dextrine  chambers;  11,  warehouse;  12, 
office;  13,  tool-room. 

Outside  of  these  buildings  there  are:  1,  the  scum- 
pit  (14);  2,  the  pit  for  the  residuum  of  grains,  offal, 
and  albumen  (15). 

For  the  making  of  starch  the  following  course  of 
operation  is  observed  in  this  establishment,  to  wit : — 

An  elevator,  with  endless  chain,  carries  the  potatoes 
from  the  cellar  to  the  washing  machine,  which  is 
mounted  in  a  corner  of  the  hall ;  1500  to  2000  kilo- 
grammes (3300  to  4400  Ibs.)  of  potatoes  are  thus  raised 
per  hour. 

The  construction  of  this  washing-machine,  as  also 
the  mechanism  of  all  the  other  machinery,  apparatus, 
and  contrivances,  has  been  described  in  the  foregoing 
pages  of  this  treatise. 

The  general  principle  on  which  the  drying-rooms  are 
constructed  is  entirely  identical  with  those  of  the  malt- 
kilns,  a  ventilation  resembling  Venitian  blinds  being 
used. 

The  roasting  apparatus  and  the  dextrine-mill  are 
placed  in  a  separate  room,  as  represented  in  the  draw- 
ing, and  are  situated  between  the  room  for  the  centri- 
fugal apparatus  and  the  dextrine  chambers. 

In  conclusion  it  may  be  stated  that  by  this  method 
and  machinery  120  kilogrammes  (264  Ibs.)  of  starch 
will  make  100  kilogrammes  (220  Ibs.)  of  excellent 
dextrine. 

In  the  manufacture  of  starch  in  this  establish- 
ment, the  following  modus  operandi  is  observed:  A 


314  MANUFACTURE    OF    STARCH,    ETC. 

chain-pump  work  carries  the  potatoes  from  the  cellar 
to  the  washing-machine,  which  is  placed  in  the  same 
room  with  the  grater.  From  1500  to  2000  kilo- 
grammes (3300  to  4400  Ibs.)  per  hour,  or  25  to  33 
kilogrammes  (55  to  72.6  Ibs.)  per  minute  of  potatoes  are 
thus  hoisted  up.  The  construction  of  this  washing 
apparatus  has  been  fully  described;  its  capacity  is  25 
revolutions  per  minute.  The  perfectly  cleansed  pota- 
toes roll  over  an  inclined  plane  to  the  potato  grater, 
which  makes  900  to  1000  revolutions  a  minute,  while 
the  driving  machine  executes  from  90  to  100  strokes 
per  minute.  The  water  supply,  by  which  the  grater 
is  fed,  amounts  to  40  litres  (10.56  gallons)  per  hour. 
A  pump,  making  30  strokes  per  minute,  carries  the 
fine  potato-paste  to  the  extraction  machine.  The  brush- 
cylinders  make  24  to  30  revolutions  per  minute,  and 
the  water  supply  of  this  apparatus  amounts  to  from 
300  to  350  litres  (79.2  to  92.4  gallons)  per  minute. 
The  starch-milk  extracted  runs  from  thence  upon  the 
repassing-sieve,  and  the  shaking-sieve,  and  from  there 
into  the  "sedimenteurs"  (settling  tanks),  which  have  a 
capacity  of  20,000  kilogrammes  (44,000  Ibs.)  of  starch- 
milk,  the  quantity  manufactured  per  day. 

The  washing  water  resulting  from  the  cleaning  of 
the  potatoes  runs  through  a  subterranean  culvert  into 
the  scum-pit,  where  the  solid — mostly  earthy — parts 
are  settling,  and  which  furnish  an  excellent  fertilizer. 
The  pulp  thrown  out  by  the  extracting  machine,  the 
repassing-  and  shaking-sieves,  is  collected  in  the  re- 
turn-pit, and  furnishes  a  food  for  domestic  animals. 

In  the  room  for  the  starch-washing  apparatus  are 
four  laveurs  (wash  drums),  three  of  them  serving  for 
the  reception  of  the  first  product,  while  the  fourth  is 
designed  to  receive  the  starch  phlegm.  When  the 


THE    TECHNOLOGY   OF    DEXTRINE.  315 

starch  in  the  sedimenteurs  has  settled,  the  water  above 
the  starch  is  conducted  by  means  of  an  elastic  siphon 
to  the  albumen  sink,  which  is  of  a  corresponding  size 
to  the  requirements  of  the  factory.  The  albumen  is 
precipitated  by  the  application  of  lime-milk,  and  after 
its  setting  the  water  above  it  is  drained  off. 

The  starch  in  the  sedimenteur  is  then  placed  in  the 
laveur,  where  it  is  washed  out  with  pure  water.  The 
process  of  washing  being  done,  and  the  starch  left  to 
settle,  the  water  above  it  is  removed  by  a  siphon,  and 
the  separating  of  the  starch  from  the  scum-layer  above 
it  is  attended  to. 

For  the  reception  and  other  manipulation  of  the 
starch-phlegm  one  and  the  same  laveur  serves,  and  in 
it  the  starch  is  mixed  with  water,  then  pumped  up 
by  means  of  a  prmp  into  the  stirring-tub,  and  from 
thence  conducted  to  a  shaking-sieve,  which  is  placed 
in  the  same  room  in  which  the  centrifugal  apparatus  is 
mounted.  The  milk  running  off  from  this  sieve  runs 
into  the  sedimenteurs  for  furnishing  the  second  pro- 
duct, four  of  which  are  placed  in  a  room.  Here  the 
depositing  of  the  starch  takes  place,  while  the  separated 
cellulose  is  carried  to  the  cellulose-pit.  The  starch, 
free'd  of  its  phlegm-layer,  is  again  washed  once  or 
twice,  thereupon  mixed  up  to  a  dense  starch-milk,  and 
by  means  of  another  pump  lifted  into  the  stirring-tub, 
now  to  be  conducted  to  the  centrifugal  apparatus. 

If  the  product  is  to  be  disposed  of  as  starch,  or  for 
the  manufacture  of  dextrine,  the  starch  after  having 
passed  the  centrifugal  machine  is  expedited  to  the 
drying  rooms,  which  consist  of  four  chambers,  and  are 
also  used  for  the  manufacture  of  dextrine. 

In  producing  dextrine,  the  starch  is  previously  pre- 


3i6  MANUFACTURE    OF    STARCH,    ETC. 

pared  by  a  diluted  mineral  acid.  This  is  manipulated 
by  manual  labor  in  the  so-called  mixing  troughs.  But 
as  this  dough  is  very  stiff,  the  eqiial  kneading  of  the 
starch  with  the  sour- water  is  a  laborious  job,  and  hence 
kneading  machines  may  be  profitably  applied  for  this 
purpose. 


APPENDIX. 


THE  METRIC  SYSTEM  OF  WEIGHTS  AND  MEASURES. 

THE  United  States  being  the  first  to  introduce  the  decimal 
system  into  the  coinage  of  the  country,  and  to  demonstrate  its 
superior  utility,  it  is  remarkable  that  we  have  hesitated  so  long 
in  regard  to  the  substitution  of  the  same  simple  and  rational 
system  of  weights  and  measures  for  the  complicated  and  con- 
fused standards  in  general  use. 

In  May,  1866,  the  Committee  on  Coinage,  Weights,  and  Mea- 
sures presented  to  the  House  of  Representatives  an  exhaustive* 
report,  accompanied  by  bills  authorizing  the  introduction  of 
the  metric  system  into  the  various  departments  of  trade,  and 
making  all  contracts,  based  on  this  system  of  weights  and 
measures,  valid  before  any  court  in  the  United  States.  They 
said : — 

"THE  METRIC  SYSTEM. 

"It  is  orderly,  simple,  and  perfectly  harmonious,  having  use- 
ful relations  between  all  its  parts.  It  is  based  on  the  METER, 
which  is  the  principal  and  only  arbitrary  unit.  The  meter  is  a 
measure  of  length,  and  was  intended  to  be,  and  is,  very  nearly 
one  ten-millionth  of  the  distance  on  the  earth's  surface  from 
the  equator  to  the  pole.  It  is  39.37  inches,  very  nearly. 

"The  are  is  a  surface  equal  to  a  square  whose  side  is  10 
meters.  It  is  nearly  four  square  rods. 

"The  liter  is  the  unit  for  measuring  capacity,  and  is  equal  to 
the  contents  of  a  cube  whose  edge  is  a  tenth  part  of  the  meter. 
It  is  a  little  more  than  a  wine  quart. 

"  The  gramme  is  the  unit  of  weight,  and  is  the  weight  of  a 
cube  of  water,  each  edge  of  the  cube  being  one  one-hundredth 
of  the  meter.  It  is  equal  to  15.432  grains. 

"  The  stere  is  the  cubic  meter. 

"Each  of  these  units  is  divided  decimally,  and  larger  units 
are  formed  by  multiples  of  10,  100,  &c.  The  successive  mul- 
tiples are  designated  by  the  prefixes,  dtka,  hecto,  kilo,  and  myria  ; 
the  subordinate  parts  by  deci,  centi,  and  milli,  each  having  its 
own  numerical  significance. 

"  The  nomenclature,  simple  as  it  is  in  theory,  and  designed 
21  1 


318  THE    METRIC    SYSTEM.' 

from  its  origin  to  be  universal,  can  only  become  familiar  by 
use.  Like  all  strange  words,  these  will  become  familiar  by 
custom,  and  obtain  popular  abbreviations.  A  system  which 
has  incorporated  with  itself  so  many  different  series  of  weights, 
and  such  a  nomenclature  as  'scruples,'  'pennyweights,'  'avoir- 
dupois,' and  with  no  invariable  component  word,  can  hardly 
protest  against  a  nomenclature  whose  leading  characteristic  is  a 
short  component  word  with  a  prefix  signifying  number.  We 
are  all  familiar  with  thermometer,  barometer,  diameter,  gasometer, 
&c..  with  telegram,  monogram,  &c.,  words  formed  in  the  same 
manner. 

"After  considering  every  argument  for  a  change  of  nomen- 
clature, your  committee  have  come  to  the  conclusion  that  any 
attempt  to  conform  it  to  that  in  present  use  would  lead  to  con- 
fusion of  weights  and  measures,  would  violate  the  early  learned 
order  and  simplicity  of  metric  denomination,  and  would  seri- 
•ously  interfere  with  that  universality  of  system  so  essential  to 
international  and  commercial  convenience. 

"  When  it  is  remembered  that  of  the  value  of  our  exports 
and  imports,intheyear  ending  June  30, 1860,  in  all  $762,000,000, 
the  amount  of  near  $700,000,000  was  with  nations  and  their  de- 
pendencies that  have  now  authorized,  or  taken  the  preliminary 
steps  to  authorize,  the  metric  system,  even  denominational  uni- 
formity for  the  use  of  accountants  in  such  vast  transactions 
assumes  an  important  significance.  In  words  of  such  universal 
employment,  each  word  should  represent  the  identical  thing  in- 
tended, and  no  other,  and  the  law  of  association  familiarizes  it. 

"Your  committee  unanimously  recommend  the  passage  of 

the  bills  and  joint  resolutions  appended  to  this  report 

The  metric  system  is  already  used  in  some  arts  and  trades  in 
this  country,  and  is  especially  adapted  to  the  wants  of  others. 
Some  of  its  measures  are  already  manufactured  at  Bangor,  in 
Maine,  to  meet  an  existing  demand  at  home  and  abroad.  The 
manufacturers  of  the  well-known  Fairbanks'  scales  state:  'For 
many  years  we  have  had  a  large  export  demand  for  our  scales 
with  French  weights,  and  the  demand  and  sale  are  constantly 
increasing.'  Its  minute  and  exact  divisions  specially  adapt  it 
to  the  use  of  chemists,  apothecaries,  the  finer  operations  of  the 
artisan  and  to  all  scientific  objects.  It  has  always  been  and  is 
now  used  in  the  United  States  coast  survey.  Yet  in  some  of 
the  States,  owing  to  the  phraseology  of  their  laws,  it  would  be 
a  direct  violation  of  them  to  use  it  in  the  business  transactions  of 
the  community.  It  is,  therefore,  very  important  to  legalize  its  use, 
and  to  give  to  the  people,  or  that  portion  of  them  desiring  it,  the 
opportunity  for  its  legal  employ ment,  while  the  knowledge  of 
its  characteristics  will  be  thus  diffused  among  men." 


WEIGHTS    AND    MEASURES.  319 


WEIGHTS  AND  MEASURES. 
APOTHECARIES'  WEIGHT,  U.  S. 

Pound.  Ounces.  Drachms.  Scruples.  Grains. 

Ibl        =        12        =        96        ==        283  =  5760 

§    1        =          8        =          24  =  480 

3!=            3  =  60 

&1  =  gr.  20 

The  imperial  standard  Troy  weight,  at  present  recognized  by  the  British 
laws,  corresponds  with  the  apothecaries'  weight  in  pounds,  ounces,  and 
trrains,  but  differs  from  it  in  the  division  of  the  ounce,  which,  according  to 
the  former  scale,  contains  twenty  pennyweights,  each  weighing  twenty- 
four  grains. 

AVOIRDUPOIS  WEIGHT. 

Pound.  Ounces.  Drachms.  Troy  grains. 

lb  1        =        16        =        256        =        7000. 
oz.    1        =          16        =          437.5 

dr.    1        =  27.34375 

Relative  Value  of  Troy  and  Avoirdupois  Weights. 

Pound.  Pounds.  Pound.      Oz.         Grains. 

1  Troy  =    0.822857  Avoirdupois  =    0        13        72.5 

1  Avoirdupois  =     1.215277  Troy  =1          2      280. 

WINE  MEASURE,  U.  S. 

Gallon.        Pints.    Fluidounces.     Fluidrachms.      Minims.     Cubic  inches. 

Cong.  1     =    8    =    128      =      1024  =  61440  =  231. 

0 1    =      16      =        128  =  7680  =    28.875 

f§    1      =            8  =  480  =      1.8047 

f5  1  =  TH.  60  =      0.2256 

IMPERIAL  MEASURE. 

Adopted  by  all  the  British  College. 

Gallon.  Pints.        FJuidounces.       Fluidrachms.  Minims. 

1       =      8      =      160        =      1280  =  76800 

1      =        20        =        160  =  9600 

1        =           8  =  480 

1  =  60 

Relative  Value  of  Apothecaries1  and  Imperial  Measures. 
APOTHECARIES'  MEASURE.  IMPERIAL  MEASURE. 

Pints.        Flnidozs.       Flaidrms.        Minims. 

1  gallon          =  6            13               2  23 

1  pint              =  16               5  18 

1  flmdounce  =  1               0  20 

1  fluidrachm  =  1  2.5 

1  minim          =  1.04 

IMPERIAL  MEASURE.  APOTHECARIES'  MEASURE. 

Gallon.     Pints.     Fluidox.     Fluidrms.  Minims 

1  gallon          =11958 
1  pint  =  1  3  1          38 

1  fluidounce   =  7          41 

1  fluidrachm  =  .  58 

1  minim          =  0.96 


320  WEIGHTS  'AND   MEASURES. 

Relative  Value  of  Weights  and  Measures  in  Distilled  Water  at  GQ°  Fahr. 

1.  Value  of  Apothecaries'  Weight  in  Apothecaries'  Measure. 

Pints.      Fluidoz.    Fluidr.        Minims. 

1  pound  =  0.7900031  pints               =0            12            5  7.2C38 

1  ounce  =  1.0533376  fluidoimces   =0              1            0  25.6020 

1  drachm  =  1.0533376  fluidrachms  =     001  3.20(2 

1  scruple  =  0              0            0  21  0607 

1  grain  =  000  1.0533 

2.  Value  of  Apothecaries'  Measure  in  Apothecaries'  Weight. 

Pounds.   Oz.  Dr.  Sc.       Gr.  Grains. 

1  gallon          =  10.12654270  pounds  =  10    1     4    0  8.88  =  58328.886 

1  pint               =    1.26581783  pounds  =     1311  11.11=    7291.1107 

I  fluiaounce   =    0.94936332  ounces  =     0    0     7     1  15.69=      455.6944 

1  fluidrachm  =     0.94936332  drms.     =0002  16.96  =        56.9618 

1  minim          =    0.94936332  grains    =  1.9493 

3.  Value  of  Avoirdupois  Weight  in  Apothecaries'  Measure. 

Pints.    Fluidozs.    Fluidrms.     Min'ms. 

1  pound  =    0.9600732  pints  =0  15          2  53.3622 

1  ounce  =    0.9600732  fluidounces    =0  07  40.8351 

4.  Value  of  Apothecaries'  Measure  in  Avoirdupois  Weight. 

1  gallon          =     8.33269800  pounds. 
1  pint  =    1.04158725  pounds. 

1  fluidounce   =     1.04158725  ounces. 

5.  Value  of  Imperial  Measure  in  Apothecaries'  and  Avoirdupois  Weights. 

Imperial  Measure.    .Apothecaries' Weight.    Avoirdupois  Weight.  Grains.     Cubic  inches. 

1  gallon          =  12  tt>  1  §  65  29  0  gr.  =  10  Ib  0 1  =70,000      =277.27384 

1  pint  =161      2    10       =14=  8,750      =  34.65923 

1  fluidounce   =  7      0     17.5    =  1     =      437.5  =     1.733W5 

1  fluidrachm  =  2     14.69=  54.69=    0.21662 

1  minim          =  0.91=    0.00361 

In  converting  the  weights  of  liquids  heavier  or  lighter  than  water  into 
measures,  or  conversely,  a  correction  must  be  made  for  specific  gravity.  In 
converting  weights  into  measures,  the  calculator  may  proceed  asif  the  liquid 
was  water,  and  the  obtained  measure  will  be  the  true  measure  inversely  as 
the  specific  gravity.  In  the  converse  operation,  of  turning  measures  into 
weights,  the  same  assumption  may  be  made,  and  the  obtained  weight  will 
be  the  true  weight  directly  as  the  specific  gravity. 

4 


TABLES 

SHOWING  THB 

RELATIVE  VALUES  OP  FRENCH  AND  ENGLISH  WEIGHTS 
AND  MEASURES,  &c. 


Measures  of  Length. 

Millimetre  =         0.03937  inch. 

Centimetre  =          0.393708         " 

Decimetre  =          3.937079  inches. 

Metre  =        39.37079 

"  =         3.2808992  feet. 

«  =          1.093633  yard. 

Decametre  =        32.808992  feet. 

Hectometre  =      328.08992  " 

Kilometre  =    3280.8992  « 

"  =    1093.633  yards. 

Myriametre  =  10936.33  " 

"  =          6.2138  miles. 

2.539954  centimetres. 

3.0479449  decimetres. 

0.91438348  metre. 
1.82876696     " 

5.029109  metres. 
201.16437  " 

1609.3149  « 

1852  « 


Inch  (7V  yard) 

Foot  (i  yard) 

Yard 

Fathom  (2  yards) 

Pole  or  perch  (5£  yards) 

Furlong  (220  yards) 

Mile  (1760  yards) 

Nautical  mile 


322 


VALUES   OF   FRENCH  AND  ENGLISH 


Superficial  Measures. 

Square  millimetre  =  ^        square  inch. 


centimetre  •• 

decimetre 

ti 

metre  or  centiare 

U  II 


Are 


Hectare 

« 

Square  inch 
<(         <t 

"       foot 

"      yard 

"       rod  or  perch 
Rood  (1210  sq.  yards) 
Acre  (4840  sq.  yards) 


inches. 

foot. 

inches. 

feet. 

yard 

feet. 

yards. 


0.00155          " 

0.155006,       " 

15.50059         " 

0.107643       " 

1550.05989          " 

10.764299       " 

1.196033       " 

1076.4299  " 

119.6033  " 

0.098845  rood. 

11960.3326      square  yards. 

2.471143  acres. 

645.109201  square  millimetres. 
6.451367       "      centimetres 
9.289968       "      decimetres. 
0.836097       "      metre. 
25.291939      •"      metres. 
10.116775  ares. 
0.404671  hectare. 


Measures  of  Capacity. 

Cubic  millimetre  =      0.000061027  cubic  inch. 


K 

centimetre  or 

millilitre 

=      0.061027 

tt 

tt 

10 

« 

centimetres  or 

centilitre 

=      0.61027 

tt 

tt 

100    " 

«            it 

decilitre 

= 

6. 

102705 

tt 

inches. 

1000  «'• 

U                    ft 

litre 

— 

61. 

0270515 

tt 

tt 

(( 

u 

n            t< 

ft 

= 

1. 

760773 

imp'l  pint. 

11 

u 

<t            t< 

tt 

=      0.2200967 

u 

gal'n. 

Decalitre                                      = 

610.270515 

cubic 

inches. 

" 

= 

2. 

2009668 

imp. 

gal'ns. 

Hectolitre                                     = 

3. 

531658 

cubic 

feet. 

» 

= 

22. 

009668 

imp.  gal'ns. 

Cubic  metre  or  stere  or  kilolitre  = 

1.30802 

cubic 

yard. 

" 

« 

« 

= 

35. 

3165807 

ti 

feet. 

Myrialitre                                    = 

353. 

165807 

tt 

" 

WEIGHTS  AND   MEASURES,    ETC. 


323 


Cubic  inch 
"  foot 
"  yard 


=    16.386176        cubic  centimetres. 
=i    28.315312  "     decimetres. 

=      0.764513422      "     metre. 


American  Measures. 

Winchester  or  U.S.  gallon  (231  cub.in.)        as       3.785209  litres. 

"  "     bushel(2150.42cub.in.)=      35.23719       " 

Chaldron  (57.25  cubic  feet)  =  1621.085  « 

British  Imperial  Measures. 
Gill  =    0.141983      litre. 

Pint  (£  gallon)  =    0.567932         " 

Quart  (j  gallon)  =    1.135864        " 

Imperial  gallon  (277.2738  cub.  in.)  ==    4.54345797  litres. 
Peck  (2  gallons)  =    9.0869159       " 

Bushel  (8  gallons)  =  36.347664         " 

Sack  (3  bushels)  =    1.09043        hectolitre. 

Quarter  (8  bushels)  =   2.907813      hectolitres. 

Chaldron  (12  sacks)  =  13.08516          " 


Milligramme 


Weights. 

=        0.015438395  troy  grain. 


Centigramme 

=        0.15438395      "         " 

Decigramme 

=        1.5438395 

"         « 

Gramme 

=      15.438395 

"     grains. 

it 

=        0.643 

pennyweight. 

" 

=        0.0321633 

oz.  troy. 

it 

=        0.0352889 

oz.  avoirdupois. 

Decagramme 

=    154.38395 

troy  grains. 

" 

=        5.64 

drachms  avoirdupois. 

Hectogramme 

=        3.21633 

oz.  troy. 

u 

=        3.52889 

oz.  avoirdupois. 

Kilogramme 

=        2.6803 

Ibs.  troy. 

u 

=        2.205486 

Ibs.  avoirdupois. 

Myriagramme 

=      26.803 

Ibs.  troy. 

" 

=      22.05486 

Ibs.  avoirdupois. 

Quintal  metrique  = 

100  kilog.  =    220. 

5486  Ibs.  avoirdupois. 

Tonne                      = 

1000  kilog.  =  2205. 

486      "             " 

324 


VALUES    OF   FRENCH   AND   ENGLISH 


Different  authors  give  the  following  values  for  the  gramme: — 
Gramme  =  15.44402     troy  grains. 

=  15.44242  " 

"          =  15.4402  " 

«  =  15.433159  " 

«          =  15.43234874      " 


AVOIRDUPOIS. 


Long  ton  =  20  cwt.  =  2240  Ibs.  = 

Short  ton  (2000  Ibs.)  = 

Hundred  weight  (112  Ibs.)  = 

Quarter  (28  Ibs.)  = 

Pound  =  16  oz.  =  7000  grs.  = 

Ounce  =  16  dr'tns.  =  437.5  grs.  = 

Drachm  =.  27.344  grains  = 


kilogrammes. 


1015.649 
906.8296  " 

50.78245  " 

12.6956144 

453.4148        grammes. 
28.3375 
1.77108      gramme. 


TROY  (PEECIOUS  METALS). 

Pound  =  12  oz.  =  5760  grs.         =    373.096  grammes. 
Ounce  =  20  dwt.  =  480  grs.         =      31.0913  " 

Pennyweight  =  24  grs.  =        1.55457  gramme. 

Grain  =        0,064773  " 

APOTHECARIES'  (PHARMACY). 

Ounce  =  8  drachms  =  480  grs.    =      31.0913  gramme. 
Drachm  =  3  scruples  =  60  grs.    =        3.8869  " 

Scruple  =  20  grs.  =        1.29546  gramme. 


CARAT  WEIGHT  FOR  DIAMONDS. 

1  carat  =  4  carat  grains  =  64  carat  parts. 

"         =3.2      troy  grains. 

"        =  3.273   "        " 

«        ==  0.207264  gramme 

«        _  0.212  " 

«  =  0.205  " 

Great  diversity  in  value. 
8 


WEIGHTS  AND   MEASURES,   ETC.  325 

Proposed  Symbols  for  Abbreviations. 


M  —  myria  — 

10000 

Mm 

Mg 

Ml 

K—  kilo      — 

1000 

Km 

Kg 

Kl 

H  —  hecto   — 

100 

Hm 

Hg 

HI 

Ha 

D  —  deca     — 

10 

Din 

Dg 

Dl 

Da 

Unit 

1 

metre  —  m 

gramme—  g 

litre—  1 

are  —  a 

,1—  deci      — 

0.1 

dm 

dg 

dl 

da 

c  —  centi     — 

0.01 

cm 

eg 

cl 

ca 

m  —  milli    — 

0.001 

in  in 

mg 

ml 

Km  =  Kilometre.  HI  =  Hectolitre.  eg  =  centigramme. 
c.  cm  =  cm3  =  cubic  centimetre,  dm2  =  sq.  dm  =  square  deci- 
metre. Kgm  =  Kilogrammetre.  Kg0  =  Kilogramme  degree. 


Celsius  or  Centigrade. 

Fahrenheit. 

Reaumur. 

—   15° 

4-    5° 

—   12° 

—  10 

+  14 

—      8 

—     5 

+  23 

—    4 

0  melting 

-f  32 

ice          0 

h     5 

+  41 

-f    4 

-  10 

4-  50 

-     8 

-  15 

-f  59 

h  12 

-  20 

+  68 

-  16 

-  25 

+  77 

r-  20 

-  30 

-f-  86 

-  24 

-  35 

+  95 

+  28 

-  40 

+104 

+  32 

-  45 

+  113 

+  36 

-  50 

+122 

+  40 

-  55 

+131 

+  44 

-  60 

+140 

+  48 

-  65 

+149 

+  52 

-  70 

+158 

+  56 

-  75 

+167 

-  60 

-  80 

+176 

-  64 

-  85 

+185 

-  68 

-  90 

+194 

-  72 

4-  95 

4-203 

+  76 

hi  00  boiling 

+212 

water  +  80 

-200 

+392 

+  160 

-300 

+572 

+240 

-400 

+752 

+320 

-500 

+932 

+400 

326 


VALUES   OF   FRENCH  AND   ENGLISH 


1°  C.  =  1°.8  Ft.  =  f°  Ft.  =  0°.S  R.  =  f°  R. 
C.  x  f  =  1°  Ft.   1°  Ft.  X  t  =  1°  C.   1°  R.  X  f  =1°  Ft. 
C.  x  i  =  1°  R.   1°  Ft.  X  t  =  1°  R.   1°  R.  X  f  =1°  C. 


English. 


Calorie  (French)  =  unit  of  heat 

=  kilogramme  degree 
It  is  the  quantity  of  heat  necessary  to  raise  1°  C.  the  tempera- 
ture of  1  kilogramme  of  distilled  water. 

Kilogrammetre  =  Kgm  =  the  power  necessary  to  raise  1  kilo- 
gramme, 1  metre  high,  in  one  second.  It  is  equal  to  ^  of  a 
French  horse  power.  An  English  horse  power  =  550  foot  pounds, 
while  a  French  horse  power  =  542.7  foot  pounds. 

Ready-made  Calculations. 


No. 
of 
units. 

Inches  to 
centimetres. 

Feet  to 
metres. 

Yards  to 
metres. 

Miles  to 
Kilometres. 

Millimetres 
to  inches. 

1 

2.53995 

0.3047945 

0.91438348 

1.6093 

0.03937079 

2 

5.0799 

0.6095890 

1.82876696 

3.2186 

0.07874158 

3 

7.6199 

0.9143835 

2.74315044 

4.8279 

0.11811227 

4 

10.1598 

1.2197680 

3.65753392 

6.4373 

0.15748316 

5 

12.6998 

1.5239724 

4.57191740 

8.0466 

0.19685395 

6 

15.2397 

1.8287669 

5.48630088 

9.6559 

0.23622474 

7 

17.7797 

2.1335614 

6.40068436 

11.2652 

0.27559553 

8 

20.3196 

2.4383559 

7.31506784 

12.8745 

0.31496632 

9 

22.8596 

2.7431504 

8.22945132 

14.4838 

0.35433711 

10 

25.3995 

3.0479450 

9.14383480 

16.0930 

0.39370790 

No. 
of 
nnits. 

Centimetres 
to  inches. 

Metres  to 
feet. 

Metres  to 
yards. 

Kilometres 
to  miles. 

Square  inches 
to  square 
centimetres. 

1 

0.3937079 

3.2808992 

1.093633 

0.6213824 

6.45136 

2 

0.7874158 

6.5617984 

2.187266 

1.2427648 

12.90272 

3 

1.1811237 

9.8426976 

3.280899 

1.8641472 

19.35408 

4 

1.5748316 

13  1235968 

4.374532 

2.4855296 

25.80544 

5 

1.9685395 

16.4044960 

5.468165 

3.1089120 

32.25680 

6 

2.3622474 

19.6853952 

6.561798 

3.7282944 

38.70816 

7 

2.7559553   22.9662944 

7.655431 

4.3496768 

45.15952 

8 

3.1496632  26.2471936 

8.749064 

4.9710592 

51.61088 

9 

3.5433711   29.5280928 

9.842697 

5.5924416 

58.06224 

10 

3.9370790 

32.8089H20 

10.936330 

6.2138240 

64.51360 

10 


WEIGHTS   AND   MEASURES,   ETC. 


327 


No. 
of 
units. 

Square  feet  to 
sq.  metres. 

Sq.  yards  to 
sq.  metres. 

Acres  to 
hectares. 

Square 
centimetres 
to  sq.  inches. 

Sq.  metres 
to  sq.  feet. 

1 

0.0929 

0.836097 

0.404671 

0.155 

10.7643 

2 

0.1858 

1.672194 

0.809342 

0.310 

21.5286 

3 

0.2787 

2.508291 

1.204013 

0.465 

32.2929 

4 

0.3716 

3.344388 

1.618684 

0.620 

43.0572 

5 

0.4645 

4.180485 

2.023355 

0.775 

53.8215 

6 

0.5574 

5.016582 

2.428026 

0.930 

64.5858 

7 

0.6503 

5.852679 

2.832697 

1.085 

75.3501 

8 

0.7432 

6.688776 

3.237368 

1.240 

86.1144 

9 

0.8361 

7.524873 

3.642039 

1.395 

96.8787 

10 

0.9290 

8.360970 

4.046710 

1.550 

107.6430 

No. 
of 
ticits. 

Square  met  res 
to  sq.  yards. 

Hectares 
to  acres. 

Cubic  inches 
to  cubic 
centimetres. 

Cubic  feet  to 
cubic  metres. 

Cubic  yards 
to  cubic 
metres. 

1 

1.196033 

2.471143 

16.3855 

0.02831 

0.76451 

2 

2.392066 

4.9422S6 

32.7710 

0.05662 

1.52902 

3 

3.588099 

7.413429 

49.1565 

0.08494 

2.29354 

4 

4.784132 

9.884572 

65.5420 

0.11325 

3.05805 

5 

5.980165 

12.355715 

81.9275 

0.14157 

3.82257 

6 

7.176198 

14.826858 

98.3130 

0.16988 

4.58708 

7 

8.372231 

17.298001 

114.6985 

0.19819 

5.35159 

8 

9.568264 

19.769144 

131.0840 

0.22651 

6.11611 

9 

10.764297 

22.240287 

147.4695 

0.25482 

6.88062 

10 

11.960330 

24.711430 

163.8550 

0.28315 

7.64513 

No. 
of 
units. 

Cubic 
!  centimetres  to 
;  cubic  inches. 

Litres  to 
cubic  inches. 

Hectolitres  to 
cubic  feet. 

Cubic  metres 
to  cubic  feet. 

Cubic  metres 
to  cubic 
yards. 

1 

0.06102 

61.02705 

3.5317 

35.31659 

1.30802 

2 

0.12205 

122.05410 

7.0634 

70.63318 

2.61604 

3 

0.18308 

183.08115 

10.5951 

105.94977 

3.92406 

4 

0.24411 

244.10820 

14.1268 

141.26636 

5.23208 

5 

0.30514 

305.13525 

17.6585 

176.58295 

6.54010 

6 

0.36617 

366.16230 

21.1902 

211.89954 

7.84812 

7 

0.42720 

427.18935 

24.7219 

247.21613 

9.15614 

8 

0.48823 

488.21640 

28.2536 

282.53272 

10.46416 

9 

0.54926 

549.24345 

31.7853 

317.84931 

11.77218 

10 

0.61027 

610.27050 

35.3166 

353.16590 

13  08020 

11 


328        FRENCH  AND  ENGLISH  WEIGHTS,   ETC. 


No. 
of 
units. 

Grains 
to  grarnmes. 

Ounces  avoir, 
to  grammes. 

Ounces  troy 
to  grammes. 

Pounds  avoir, 
to 
kilogrammes. 

Pounds  troy 
to 
kilogrammes. 

1 

0.064773 

28.3375 

31.0913 

0.4534148 

0.373096 

2 

0.129546 

56.6750 

62.1826 

0.9068296 

0.746192 

3 

0.194319 

85.0125 

93.2739 

1.3602444 

1.119288 

4 

0.259092 

113.3500 

124.3652 

1.8136592 

1.492384 

5 

0.323865 

141.6871 

155.4565 

2.2670740 

1.865480 

6 

0.388638 

170.0250 

186.5478 

2.7204888 

2.238576 

7 

0.453411 

198.3625 

217.6391 

3.1739036 

2.611672 

8 

0.518184 

226.7000 

248.7304 

3.6273184 

2.984768 

9 

0.582957 

255.0375 

279.8217 

4.0807332 

3.357864 

10 

0.647730 

283.3750 

310.9130 

4.5341480 

3.730960 

Pounds  per 

No. 

Long  tons  to 

square  inch  to    Grammes  to 

Grammes  to 

Grammes  to 

of 

tonnes  of  1000 

kilogrammes 

grains. 

ounces  avoir. 

ounces  troy. 

units. 

kilog. 

per  square 

centimetre. 

1 

1.015649 

0.0702774 

15.438395 

0.0352889 

0.0321633 

2 

2.031298 

0.1405548 

30.876790 

0.0705778 

0.0643266 

3 

3.046947 

0.2108322 

46.315185 

0.1058667 

0.0964899 

4 

4.062596 

0.2811096 

61.753580 

0.1411556 

0.1286532 

5 

5.078245 

0.3513870 

77.191975 

0.1764445 

0.1608165 

6 

6.093894 

0.4216644 

92.630370 

0.2117334 

0.1929798 

7 

7.109543 

0.4919418  1  108.  068765 

0.2470223 

0.2251431 

8 

8.125192 

0.5622192    123.507160 

0.2823112 

0.2573064 

9 

9.140841 

0.6324966    138.945555 

0.3176001 

0.2894697 

10 

10.156490 

0.7027740    154.383950 

0.3528890 

0.3216330 

Metric  tonnes 

Kilog.  per 

Kilog.  per 

No. 

Kilogrammes 

Kilogrammes 

of  1000  kilog. 

square  milli- 

square centi- 

of 

to  pounds 

to  pounds 

to  iong  tons  of 

metre  to 

metre  to 

units. 

avoirdupois. 

troy. 

2240  pounds. 

pounds  per 

pounds  per 

square  inch. 

square  inch. 

1 

2.205486 

2.6803 

0.9845919 

1422.52 

14.22526 

2 

4.410972 

5.3606 

1.9691838 

2845.05 

28.45052 

3 

6.616458 

8.0409 

2.9537757 

4267.57 

42.67578 

4 

8.821944 

10.7212 

3.9383676 

5690.10 

56.90104 

5 

11.027430 

13.4015 

4.9229595 

7112.63 

71.12630 

6 

13.232916 

16.0818 

P.9l»75514 

8535.15 

85.35156 

7 

15.438402 

18.7621 

6.8921433 

9957.68 

99.57682 

8 

17.643888 

21.4424 

7.8767352 

11380.20 

113.80208 

9 

19.849374 

24.1227 

8.8613271 

12802.73 

128.02734 

10 

22.054860 

26.8030 

9.8459190 

14225.26 

142.25260 

HYDROMETERS    AND    THERMOMETERS. 


HYDROMETERS  AND  THERMOMETERS. 


329 


An  areometer  is  a  convenient  glass  instrument  for  measuring  the 
density  or  specific  gravity  of  fluids.  Areometer  and  hydrometer 
are  synonymous  terms,  the  first  being  derived  from  the  Greek 
words  apcuoj,  rare,  and  fi«rpov,  measure;  and  the  latter  from  v6wp, 
water,  and  /tffpov,  measure;  hence  the  same  instrument  is  fre- 
quently denominated  both  hydrometer  and  areometer.  This  appa- 
ratus is  often  referred  to  throughout  this  work;  for  instance,  in^ 
speaking  of  alcohol,  or  lye,  their  strength  is  stated  as  being  of  so 
many  degrees  (17°  or  36°)  Baume',  that  is,  its  force  or  value  is  of 
that  specific  gravity,  corresponding  with  the  degree  to  which  the 
hydrometer  sinks  in  either  the  alcohol  or  alkaline  solution.  But, 
for  those  liquids  lighter  or  rarer  than  water,  viz.,  alcohol,  ethers, 
etc.,  the  scale  is  graduated  differently  than  for  the  heavier  or 
more  dense,  examples  of  which  are  the  acids,  saline  solutions, 
syrups,  and  the  like.  There  are  several  kinds  of  hydrometers ; 
but  that  called  Baumd's  is  the  most  used,  and  to  this  our  remarks 
are  applied. 

They  are  blown  out  of  a  piece  of  slender  glass  tubing,  and  of  the 
form  shown  by  Figs.  53  and  54  ;    A  being  the  stem  containing  the 

Fig.  53.  Fig.  54. 


graduated  paper  scale,  B  the  bulb  portion,  and  D  the  small  globes 
containing  mercury  or  shot,  serving  as  ballast  to  maintain  the 
instrument  in  an  upright  position,  when  it  is  placed  in  a  liquid. 

The  graduation  is  accomplished  by  plunging  it  into  distilled 
water  of  58°  F.,  and  weighting  the  globe  with  shot  or  mercury, 
until  the  instrument  sinks  to  the  line  a,  which  is  its  zero  point. 
This  zero  point  thus  determined  is  to  be  marked  accurately  upon 

13 


330  HYDROMETERS   AND   THERMOMETERS. 

the  glass  or  its  accompanying  paper  scale,  and  the  instrument 
again  plunged  into  ninety  parts  of  distilled  water,  holding  in  solu- 
tion ten  parts  of  previously  dried  chloride  of  sodium  or  common 
salt.  The  point  to  which  it  sinks  in  this  liquid,  say  6,  for  instance, 
is  then  also  marked  carefully  upon  the  scale,  and  rated  as  ten 
compared  with  its  zero  point.  The  interval  between  these  two 
points  is  then  spaced  off  into  ten  equal  divisions,  according  to 
which  the  remainder  of  the  tube  is  graduated  so  that  each  degree 
is  intended  to  represent  a  density  corresponding  to  one  per  cent,  of 
the  salt. 

The  above  mode  of  graduating  refers  to  the  hydrometer  for 
liquids  denser  than  water,  but  that  for  the  liquids  rarer  than  water 
is  a  little  different  from  the  preceding  in  form,  and  necessarily  has 
a  modified  scale,  which  is  graduated  as  is  shown  by  Fig.  54.  The 
instrument  should  be  sufficiently  heavy  in  ballast  to  sink  in  a 
saline  solution  of  ten  parts  of  dried  chloride  of  sodium  in  ninety 
parts  distilled  water  to  the  bottom  of  its  stem  «,  to  be  marked  as 
the  zero  of  the  scale. 

.Now,  when  it  is  again  placed  in  distilled  water  alone,  it  floats  or 
sinks  to  a  point  somewhere  about  6,  which  is  to  be  the  ten  degree 
mark.  The  rest  of  the  stem  is  then  to  be  accurately  divided  into 
as  many  ten  degree  intervals  as  its  length  will  permit,  and  each 
subdivision  into  ten  uniform  smaller  degrees  or  intervals. 
Fig.  55.  As  it  would  be  troublesome,  and  with  many  impracti- 
cable, to  estimate  the  specific  gravities  of  their  liquids 
in  a  scientific  way,  these  little  instruments  are  a  great 
convenience,  for  by  taking  out  a  portion  of  the  fluid  to 
be  tested,  and  placing  it  in  a  glass  cylinder,  Fig  55,  its 
degree  Baume*  may  be  ascertained  by  noting  the  point 
to  which  a  hydrometer  sinks  therein,  and  afterwards 
its  specific  gravity,  by  comparing  that  with  its  corre- 
sponding degree  in  the  table.  For  instance,  suppose 
the  hydrometer  sinks  in  alcohol  to  35°,  then  its  specific 
gravity  is  0.8538,  and  this  again  can  be  translated  into 
its  absolute  spirit  strength  by  comparison  with  any 
accurately  calculated  alcohol  tables.  So,  also,  if  a 
hydrometer  for  liquids  denser  than  water  sinks  in  lye 
to  26°,  it  denotes  that  the  lye  has  a  specific  gravity  of 

14 


HYDROMETERS  AKD  THERMOMETERS.          331 

1.2268.  The  presence  of  foreign  matters  will  cause  the  hydro- 
meter to  give  a  false  indication,  and  it  is,  therefore,  necessary, 
when  lyes  contain  impurities,  to  follow  special  directions,  to  as- 
certain their  amount  of  caustic  alkali.  When  the  lye  is  nearly 
pure,  they  answer  satisfactorily;  and,  indeed,  under  all  circum- 
stances, they  serve  very  well  for  noting  a  progressive  increase  or 
diminution  in  the  strength  of  lyes  or  other  liquids.  The  temperature 
of  the  liquid  should  be  58°  to  60°  F.,  at  the  moment  of  testing  it. 

Thermometers The  thermometer  is  an  instrument   made  of 

glass  exclusively,  when  intended  for  practical  purposes.  Fig.  56 
shows  v/ne  with  the  scale  of  Fahrenheit,  graduated  on 
the  glass,  so  that,  when  having  been  dipped  in  liquids, 
it  may  be  easily  cleansed.  It  derives  its  name  from 
two  Greek  words,  e*pfto$,  warm,  and  ^FTPO*,  measure, 
and  is,  as  its  title  indicates,  a  measurer  of  the  variation 
of  temperature  in  bodies.  The  principle  upon  which 
it  is  constructed,  uis  the  change  of  volume  which  takes 
place  in  bodies,  when  their  temperature  undergoes  an 
alteration,  or,  in  other  words,  upon  their  expansion." 
As  it  is  necessary,  in  the  construction  of  thermometers, 
that  the  material  used  to  measure  the  change  of  tem- 
perature shall  be  of  uniform  expansion,  and  with  a 
very  distant  interval  between  its  freezing  and  boiling 
point,  as  fulfilling  these  requisites  better  than  any 
other  body,  metallic  mercury  is  generally  used.  There 
are  several  different  therm ometrical  scales,  all  con- 
structed upon  the  same  principle,  but  varying  in  their 
graduation ;  the  boiling  and  freezing  points  of  each, 
though  corresponding  in  fact,  being  represented  by 
different  numbers.  The  Fahrenheit  scale  is  most  used 
in  this  country ;  that  of  Celsius,  called  the  Centigrade, 
in  France  and  the  Continent  generally,  except  Spain 
and  Germany,  where  Reaumur's  scale  is  preferred. 
The  relation  between  the  three  scales  is  shown  by  Fig.  57.  The 
Fahrenheit  scale  is  most  convenient,  because  of  the  lesser  value 
of  its  divisions. 

In  the  graduation  of  the  scale,  it  is  only  necessary  to  have  two 
fixed  determinate  temperatures,  and  for  these  the  boiling  and 
freezing  points  of  water  are  universally  chosen.  The  scales  can 
be  extended  beyond  either  of  these  points,  by  continuing  the 

15 


332 


HYDROMETERS   AND   THERMOMETERS. 


graduation.  Those  degrees  below  zero  or  0°  have  the  minus  ( — ) 
prefixed,  to  distinguish  them  from  those  above;  thus,  55°  F.  menus 
fifty-five  degrees  above  zero,  Fahrenheit's  scale,  and  — 9°  C.,  nine 


degrees  below  zero,  Centigrade  scale.  The  thermometers  for 
general  use  very  seldom,  however,  extend  either  way  beyond  the 
boiling  and  freezing  points  of  water,  but  for  manufacturers'  use 
they  are  graduated  sometimes  to  400°  or  600°. 

Centigrade  and  Fahrenheit. — In  the  Fahrenheit  thermometer 
the  number  0°  on  the  scale  corresponds  to  the  temperature  of  a 
mixture  of  salt  and  ice — the  greatest  degree  of  cold  that  could  be 
artificially  produced  when  the  thermometer  was  originally  intro- 
duced ;  32°  (freezing  point)  corresponds  to  the  temperature  of 
melting  ice ;  and  212°  to  the  temperature  of  pure  boiling  water — 
in  both  cases,  under  the  ordinary  atmospheric  pressure  of  14.7 
pounds  per  square  inch.  Each  division  of  the  (this)  thermometer 
represents  1°  Fall.,  and  between  32°  and  212°  there  are  180°.  In 
the  Cent,  thermometer,  used  universally  in  scientific  investigations, 
1°  corresponds  to  melting  ice,  and  100°  to  boiling  water.  From 
the  freezing  to  the  boiling  point  there  are  100°. 

The  accompanying  table  shows  the  relation  of  the  Centigrade 
and  Fahrenheit  thermometer  scales,  5°  C.  being  equal  to  9°  F., 
because  the  interval  between  the  freezing  and  boiling  points  of 
water  is  divided  into  100  and  180  equal  parts,  and  these  numbers 

16 


HYDROMETERS   AND   THERMOMETERS.  333 

are  respectively  multiples  of,  or  20  times  5  and  9.  If  the  super- 
fluous 32°  on  the  F.  side  were  disposed  of,  the  mutual  translation 
of  the  scales  would  be  simple,  since  the  two  units  are  to  each 
other  inversely  as  the  number  of  them  in  any  given  range. 

To  reduce  F.  above  melting  ice  to  terms  of  C.,  32°  must  first  be 
subtracted  from  the  given  F.  temperature,  then  multiply  the  re- 
mainder by  f ;  the  product  will  be  the  C.  term  for  the  given  tem- 
perature; and  conversely  divide  C.  by  f  and  add  32  to  translate 
C.  into  F.;  to  prove  the  work,  read  the  terms  across  the  diagram 
in  the  table.  Below  melting  ice,  the  same  rules  as  given  above 
apply,  except  that  where  32  is  added  above,  it  should  be  subtracted 
here,  and  vice  versa. 

In  the  columns  at  the  right  hand  of  each  diagram  in  this  table, 
are  found  the  approximate  steam  pressures  per  square  inch,  due 
to  the  adjoining  indications  of  temperature.  The  pressure  is 
expressed  in  pounds  and  in.  atmospheres. 

The  high  pressures  are  obtained  from  the  several  authors  who 
have  deduced  and  tabulated  them  from  experiments  and  formulas 
of  Regnault  and  others ;  and  being  hypothetical,  accuracy  is  not 
claimed  for  them. 

17 


OT 

WVBRSIT7 


334 


HYDROMETERS    AND    THERMOMETERS. 


COMPARISON  OF  CENTIGRADE  AND 

IMATE   STEAM  PRESSURE  IN 

PER   SQUARE  INCH  DUE 


FAHRENHEIT  SCALES,  AND  APPROX- 
POUNDS  AND  ATMOSPHERES 
TO  THE   TEMPERATURE: 


THERMOMETER. 


Centi. 


Fahr. 


STEAM. 
NON-CONDENSING  ENGINE. 


Pres.  per 

gauge. 

Ibs. 


Total  Press^ 

Lbs.      Atmos. 


THERMOMETER. 


Centi.          Fahr 


STEAM. 
CONDENSING  ENGINE. 


Press,  per 
gauge. 


Back  Press. 
Lbs. 


260 
255 
250 
245 
240 
235 
230 
225 
220 
215 
210 
205 
200 
195 
190 
185 
180 
175 
170 
165 
160 
155 
150 
145 
140 
135 
130 
125 
120 
115 
110 
105 


500 
491 
482 
473 
464 
455 
446 
437 
[428 
[419 
410 
401 
392 
383 
374 
365 
356 
347 
338 
329 
320 
1311 
)2 
S93 
584 
575 
1266 
257 
248 
|239 
530 
521 


665 

610 

560 

515 

472 

430 

390 

354 

321 

290 

262 

235 

211 

188 

167 

148 

131 

115 

100 

85 

73 

63 

55 

45 

37 

30 

25 

19 

14 

10 

6 

3 


680 
625 
575 

530 

487 

445 

405 

369 

336 

305 

277 

250 

226 

203 

182 

163 

146 

130 

115 

100 

88 

78 

70 

60 

52 

45 

40 

34 

29 

25 

21 

18 


46. 

42. 

39. 

36. 

33. 

30. 

27.5 

25. 

23. 

20.7 

18.8 

17. 

15.3 

13.8 

12.4 

11.1 
9.0 
8.8 
7.8 
6.8 
6. 
5.3 
4.7 
4.1 
3.5 
3. 
2.7 
2.3 
1.9 
1.6 
1.4 
1.2 


100 
95 
90 
85 
80 
75 
70 
G5 
GO 
55 
50 
45 
40 
35 
30 
25 
20 
15 
10 

5 

0 

—  51 
—10 
—15 
—20 
—25 
—30 
—35 
—40 
—45 


12121 
203 

194 

1 185 
176 
167 


effective 
Lbs.» 


[t49o 
1 140 1 
131  q 
122 
113 
[104 

95 

86  J 

77 

08 

59 

50 

41 

32 

23 

14 

5 
0 

—  4 

—13 
—22 
—31 
—40 
—49 


9* 

12* 


20* 

22 

24 

25 

26 

26* 

27f 

28* 

29 


4.7 

6.2 

7.7 

9.1 

10.2 

11. 

11.9 

12.4 

12.9 

13.3 

13.6 

13.8 

13.9 


14.7      1. 


I.Us 


12. 

10. 
8.5 
7. 
5.6 
4.5 
3.7 
2.8 
2.3 
1,8 
1.4 
1.1 
.9 


0.85 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 


0.1 


*  To  be  added  to  the  pressure 
indicated  by  steam  gauge  to 
get  total  pressure  on  piston. 


M.  T.  Mines  of  Brittany, 

500  it.,  .        .        .        59  F^ 
Hydr'  chloric  Ether  boils,  52  F< 


Max.  density  of  water,  - 

Melting  Ice,  .  32  F.  =0  GJ 
Blood  freezes,  .  .  25  F. 
Castor  Oil  freezes,  .  21  F. 
Spirits  of  turpentine 
freezes, 


Brandy  freezes, 


14  F. 


— 7F. 


Mercury  freezes,       .    —40  F 
Sulphuric  Acid  (1.641) 

freezes,         .        .    —45  F. 

Greatest  artificial 

cold,      .     —  106  to  —220  F^ 


Absolute  cold,      .Jl$j 


INDEX. 


Acids,  action  of,  on  cane-sugar,  158 
effects  on,  of  gluten.  93 
manufacture  of  dextrine  by,  292-296 
relations  of  starch  to,  25,  28 
Acidulous  liquid,  contents  of,  96 
Action  of  starch-sugar,  187,  188 
Adrugnnline,  287 
Adulterations  and  impurities  in  starch, 

144-150 

in  starch,  testings  for,  147 
Air-pump  for  drying  starch,  106 
Albumen,  77 

composition  of,  178 
Albuminous  compounds,  the,  77 
Alcoholic  fermentation  alone  unable  to 

change  dextrine  into  sugar,  177 
Alcohol,  which  will  dissolve  grape  and 

cane-sugars,  188 

Alkalies,  relations  of  starch  to,  25,  30 
Allsopp's  malting  mill,  94 
Analyses,  chemical,  of  Indian-corn,  120, 

121 

of  dextrine,  305 

of  glucose  and  starch-sugar,  225 
of  grape-sugar  samples,  257-262 
of  rice  and  the  ashes  of  rice,  127, 

128 

of  wheat,  82 

Animal  charcoal  for  filtering,  221 
Animalic  liquids,  relations  of  starch  to, 

29 
Anthon    on    perfect   transformation    of 

starch  into  sugar,  194 
Anthon's  experiments  on  production  of 

dextrine  from  wood,  SCO 
experiments  on  relations  of  starch 

to  silicic  acid,  29 
experiments    on    the    solibility    of 

grape  sugar  and  alcohol,  261 
granulated  sugar,  best  in  commerce, 

composition  of,  256 
latest  improvements,  244-249 
machinery   for    grape-sugar    on   ft 

small  scale,  245 

method    for    manufacturing  grape- 
sugar,  236-239 

new  method  for  manufacturing  dex- 
trine, 293 


America,  buildings  used  by  manufactu- 
rers of  rice-starch  in,  134 
American  method  for  making  rice-starch, 

133-135 

Amidon-grille,  278,  287 
Ammonia  for  conserving  and  improving 

flour-containing  substances,  117 
for  refining  starch,  117 
liquid   for   removing    gluten    from 

wheat-starch,  117 
relations  of  starch  to,  30 
Amylon,  23 

Apparatus  for  roasting  dextrine,  285-289 
for   the    manufacture    of    glucose, 
Rossling  and  Reichhardt's,  234, 
235 

Appearance  and  value  of  starch,  17-19 
Application  of  dextrine,  309-311 
of  g'ucose  and  grape-sugar,  263 
of  starch,  150-152 
Aqueous  vegetable  decoctions,  effect  of 

starch  on,  23 
Ashy  contents  of  pure  starch,  149 

substances  in  wheat,  82 
Astringent    substances    in    starch,    re- 
moval of,  by  ammonia,  117 

Bag  filters,  206,  207 

Barford's  experiments  on  manufacturing 

chemically  pure  dextrine,  303 
Barley,  starch  in,  18,  19 
Bases,  relations  of  starch  to,  25,  30 
Beer-brewing,  use  of  grape-sugar  in,  2C3 
couleur,  268 

Krotke's,  receipt  for,  272,  273 
effect  of  starch  on.  23 
Beers,  composition  of,  183 
Beet- sugar  manufacture  in  Europe,  154 
Berger's    methods   for    manufacture  of 

rice-starch,  132 
Bertholet's  experiments  on  production  of 

dextrine  from  wood,  300 
Berzelius  on  the  different  forms  of  fibrin 

in  plants,  22 
Bleaching    and    refining    wheat-starch, 

methods  for,  116-119 
of  glucose,  hastening  of,  253 
of  rice- starch,  131 


336 


INDEX. 


Bleaching — 

of  starch,  71-73 
water  for  starch,  Leuch's,  73 
Block's  feculometer,  147 
Boiling  apparatus,  199 

by  Anthon's  method,  236 
excessive,  of   the  starch,  effect  of, 

194 

starch  for  starch-sugar,  1 97-203 
Bolting-sieve    for     potato-starch,     Sie- 

mens's,  56-58 

Bone  black  for  filtering,  221 
Bracannot's  experiments  on  production 

of  dextrine  from  wood,  300 
Bremer's    testing    dextrine  for    textile 

fabrics,  311 
Bromine  and  chlorine,  relations  of  starch 

to,  31 

Brown  and  Poison,  126 
Bruising  and  steeping  the  wheat,  86-91 
mill  or  grain  crusher,  89-91 

Candy,  use  of  grape-sugar  in  manufac- 
ture of,  263 
Cane-sugar  and   starch-sugar,  action  of 

yeast  on,  187,  188 
chemical  formula  of,  157 
must   pass    to   starch-sugar   before 

undergoing  fermentation,  187 
transformation     into    grape-sugar, 

158 

Capillair  syrup  and  sugar,  249-252 
Carbonate  of  lime,  neutralization  by,  203 
Caustic  lyes  for  separating  starch  from 

rice,  128,  129,  131,  132,  133 
potash,  action  of,  on  starch,  144 
soda  for  purifying  starch,  119. 
Cellulose,  20,  22,  23 
Centrifugal   apparatus   for    rice-starch, 

134 
machine,  Lafferty's,  240 

raw  starch,  104,  105 
machines,  65-71 
Centrifugals   arranged    for    open    train 

with  vacuum  pan,  Lafferty's,  241 
Chalk,  use  of,  204 

Champonnois's  grater  for  potatoes,  52-54 
Chemical    combinations     with     starch- 
sugar,  189 

composition  of  wheat,  82 
process  in  fermentation,  92,  93 
properties  of  dextrine,  280-282 
of  starch,  24-33 
of  starch-sugar,  187-190 
Chemically  pure  dextrine,  302,  303 

pure  dextrine,  manufacture  of,  302, 

303 

pure  starch,  characteristics  of,  23 
Chemistry  of  dextrine,  275-282 
of  glucose,  153-190 


Chemistry — 

of  starch,  17-33 

of  starch-sugar,  153-190 
Chios,  island  of,  invention  of  starch  at, 

17 

Chloride  of  lime,  for  extracting  the  yel- 
lowish pigment  from  starch,  118 
Chlorine,  relations  of  starch  to,  31 
Clay,  starch  adulterated  with,  150 
Cleaning  the  potatoes,  49-51 
Cloth  printing,  use  of  dextrine  in,  309 
Colin  andGauthier's  discovery  of  the  ef- 
fects of  iodine  as  to  starch,  31 
Colman's  method  for  making  rice-starch, 

132 

Color  for  glucose  syrup,  220 
Confectioner's  glucose,  249 
Copper  worm,  200 
Corn,  Indian,  varieties  of,  120 
Corn-starch,  finer  quality  of,  122 

first  experiments  in  making,  122 

great  power  of  stiffening,  and  white- 
ness, smoothness,  and  gloss  of, 
126 

manufacture  of,  120-127 

process  of  fermentation,  123 

uses  of,  127 
Corn,  starch  in,  18,  19 
Couleur,  268-274 
Cylinder  sieve  for  potato-starch,  55 

Decay  of  starch,  32 
Decomposition  of  starch-sugar,  187 
Depositing   trough    for   refining   wheat- 
starch,  102,  103 
Dextrine,  amount  of  in  different  grains, 

279 
and   starch -sugar,   percentages    of, 

obtained,  180,  181,  183 
production  of  by  means  of  sul- 
phuric or  muriatic  acid,  dias- 
tase, and  yeast,  165 
Anthon's  new  method  of  manufac- 
turing, 293 

application  of,  309-311  ' 
cellular  apparatus,  294-296 
chemical  properties  of,  280-282 
chemically   pure,    manufacture  of, 

302,  303 

chemistry  of,  275-282 
conditions  for  obtaining  the  largest 

quantities  of,  283 
dark  yellow,  287 

dyeing,  experiments  for  testing, 308 
formula  for,  279 

found  in  the  animal  kingdom,  279 
from  wood,   experiments  on,  300- 

302 

globulous,  282 
gum,  277 


IXDEX. 


337 


Dextrine — 

history,  literature,  and  terminology 

of,  275-278 
in  paper  making,  310 
light  yellow,  287 

manufactory,  plan  for  the  establish- 
ment of,  311-316 
manufacture  of,  275-316 
of  by  acids,  292-296 
of  by  diastase,  296-300 
of  by  roasting  of  starch,  284- 

291 

names  given  to,  277 
of  commerce,  composition  of,  305 
origin  and  formation  of,  279 

of  the  term  with  Biot  and  Per- 

soz,  277 
or  starch-gum,  transformation  into, 

25 

quality  of,  304-309 
results   from    starch    heated   with 

acids  or  diastase,  283 
roasting  apparatus,  285-289 
substance  and  nature  of,  278 
suciee,  or  dextrine  sugar,  297 
sugar,  155 
syrup,  155,  304 
testing  of  as    to   impurities   and 

adulterations,  304-309 
three  different  ways  of  manufacture, 

284 

varieties  of,  287 
^-"Various  uses  of,  309-311 
white,  287 
with  diastase,  Payen's  apparatus 

for  production  of,  298-300 
Dextrose,  155 

chemical  formula  of,  159 
Diabetes  mellitus,  156 
Diabetic  sugar,  155 
Diastase,  action  of  on  starch,  181 
effect  on  starch,  175 
has  no  effect  on  dextrine,  161 
in  the  production  of  dextrine  and 

starch-sugar,  165 

manufacture  of  dextrine  by,206-300 
rapid  transformation  of  starch  by,  ! 

195 

relations  of  starch  to,  25,  29 
transformation  of  starch  into  dex- 
trine by,  280 
Dingier,  process  for  roasting  starch  for 

dextrine,  275 
Discernment  and  determination  of  the 

kinds  of  starch,  138-1 44 
Distilling  spirits,  use  of  grape-sugar  in, 

263 
Doeberreiner's  experiments  on  dextrine, 

276    ^ 
Domestic  manufacture  of  starch,  115, 116 


Drying  chambers  for  potato-starch.  74 
process  for  potato-starch,  73-76 
room,  or  starch  kiln,  74-76 
wheat-starch,  process  of,  105-107 

Dry  ness  of  starch,  test  of,  107 

Dry  starch,  appearance  of,  23 

Dubrunfaut  on  intervert  sugar,  159 

on  the  transformation  of  starch  into 
sugar  by  means  of  malt,  184-186 

Duryea's  maizena,  126 

Dyeing  experiments  for  the  testing  of 
dextrine,  308 

East  India  syrup,  want  of  in  Europe,  191 

Economical  process  of  manufacturing 
starch,  by  Fesca,  114,  115 

Edulcoration   and    refining    of    potato- 
starch,  58-71 
of  the  starch,  103 

Elutriating  machine,  or  inclined  plane, 
61,  64 

England,  corn-starch  manufacture  in, 
124 

Erkenbrecker's   corn-starch   establish- 
ment in  Cincinnati,  124,  125 

Evaporation  by  Anthon's  method,  238 
process  of,  210 

Extracts  of  raw  barley,  wheat,  and  rye 
to  liquefy  and  saccharify  starch-paste, 
186 

Feculometer,  Block's,  147 
Fermentation  and  decay,  32 
chemical  process  in,  92,  93 
effects  of  putrid,  93 
of  starch  and  fruit  sugars,  187 
of  rice  starch  by  Berger'  method, 132 
wheat-starch  by,  85 
Fermenting    process,    duration    of,    for 

wheat,  92 

rooms    for    manufacture    of    rice- 
starch,  137 

the  bruised  ground-up  wheat,  91-96 
Fesca's  apparatus  for  starch  from  wheat 

without  grinding,  109 
new     process     of     manufacturing 

wheat-starch,  114,  115 
refining  centrifuges,  65-70 
scales  for  determining  the  specific 

gravity  of  potatoes,  43-49 
Fibrin,  22,  77 
Filtering  barrel,  206 

through  boneblack,  221 
Filters,  221 

Filter-press,  Johnson's,  208 
Flour,  testing  starch  adulterated  with, 

148 

Form  and  size  of  starch,  23 
Formation,    substance,    and   nature    of 
starch,  19-23 


22* 


338 


INDEX. 


Fouchard's  granulated  starch,  sugar  of, 
252 

Foulcroy,  experiments  of  on  transforma- 
tion of  starch  into  gum,  163 

French  and  English  weights  and  mea- 
sures, relative  values  of,  321 

Fresenius  and  Schulze's  method  for  de- 
termining the  amount  of  starch,  etc., 
in  potatoes,  42 

Fritsche's  experiments  on  dextrine,  277 

Fruit-gum,  278 

sugar  from,  155 
syrups,  263 

Gallesizing  of  wine  with  glucose,  191,192 

and  Petiotizing  wines,  203 
Gall,  process  for  improving  wines,  192 
Gentele  on  the  quantitative  determina- 
tion of  grape-sugar,  261-262 
Germany,    importance   of    glucose    and 

starch-sugar  manufacture  in,  154 
Glauber  salts  for  purifying  starch,  118 
Glen  Cove  Company,  126 
Globulin,  77 
Globulous  dextrine,  282 
Glucose  and  grape-sugar,  application  of, 

263 

and  starch-sugar,  analyses  of,  225 
from    starch,  manufacture   of, 

196 
manufactory,    description   of, 

264-266 

apparatus  for  the  manufacture  of, 
Rossling  and  Reichardt's,  234, 
235 

chemistry  of,  153-190 
grape-  or  starch-sugar,  polarization 

of,  159 
manufacture  of,  191-267 

origin  of,  153 
Maubre's  method  for  manufacture, 

230-233 
need  of,  in  Europe,  where  beet-sugar 

is  made,  191 
packing  of,  222 
produced  by  less  continued  boiling 

than  sugar,  195 

Byrup  and  starch-sugar,  manufac- 
ture of  from  starch  by  sul- 
phuric acid,  197-225 
color  for,  220 

importance  of  in  Europe,  154 
Glucosan   or    caramel,    produced    from 

starch-sugar  by  heat,  188 
Gluten  and  wheat  starch  from  flour)  110 
effects  of  acids  upon,  93 
freeing  starch  granules  from,  93 
in  Indian  corn,  121,  122 
dissolving,  122,  123 
in  wheat,  81 


Gluten- 
Martin's  treatment  of,  113 
Nash's  process  for  removing  from 

starch,  117 

processes  for  removal  from  wheat- 
starch,  119 

relation  of  starch  to,  29 
starch,  104 
utilization   of,  in   the   manufacture 

of  starch,  107,  108 
Glycose,  155 
Gobley's  iodine  reaction  for  testing  the 

adulterations  in  starch,  147,  148 
Gomme  ceriale,  287 
d' Alsace,  278 
factice,  287 
Gommeline,  278,  287 
Grain-crusher  or  bruising-mill  for  wheat, 

89-91 
Grains,  various,  containing  starch,  137, 

138 

Granulated  starch-sugar,  223,  252 
Granulose,  22 
Grapes   and   raisins,    grape- syrup    and 

grape-sugar  from,  255,  256 
Grape-sugar,  155 

Anthon's  method  of  manufacturing, 

236-239 
a  substitute  for  crystallizing  sugar, 

192 

chemical  formula  of,  157 
formation  of,  157-159 
largely   diffused   throughout   the 
vegetable  as  well  as  the  animal 
kingdom,  156 

of  commerce,  contents  of  starch- 
sugar,  267 

physical  properties  of,  159 
where  found,  and  in  what  percent- 
age, 156 
Grape-syrup   and   grape-sugar   from 

grapes  and  raisins,  255,  256 
syrup  or  glucose,  191 
Grating  the  potatoes,  52-54 
Grinding  or  grating  the  potatoes,  52-54 
Guibort's  experiments  on  dextrine,  276, 

277 
Guild  and  Garrison's  vacuum  pump,  215, 

216 
Gum-Arabic  and  dextrine,  difference  in 

appearance  of,  305 
dextrine  as  a  substitute  for,  309 
Gum,  artificial  from  potato-starch,  309 

in  wheat,  82 
Gun  cotton,  22 

Gypsum,  starch  adulterated  with,  test- 
ing, 148,  149 

Habich,  annotations  of,  on  Pay  en,  181- 
183 


INDEX. 


339 


Hall's  process  for  extracting  the  yellow 

pigment  from  starch,  72,  118 
Heat,  effect  of,  on  starch-sugar,  188 
Histogenesis,  or  the  formation  of  tissue, 

77 
History  of  starch,  17 

sugar,  153 
Honey  and  manna,  test  of  grape-sugar 

in,  268 
sugar,  155 

Huntley  and  Palmer,  126 
Hydrometers  and  thermometers,  329 
Hydroscopic    water    in    starch-yielding 
grains  and  potatoes,  19 

Impurities  and  adulterations  in  starch, 

144-150 

of  dextrine,  304-309 
of  starch-sugar,  256-263 
in  manufacture  of  rice-starch,  treat- 
ment of,  130 
Imponderable  syrup,  197 
Inclined  plane  or  elutriating  machine, 

61,  64 

Indian  corn,  anatomical  structure  and 
qualitative  chemical  condi- 
tion, 121 

chemical  analyses  of,  120, 121 
gluten  in,  121,  122 
or  maize,  varieties  of,  120 
Ingredients  for  grape-sugar  by  Anthon's 

method,  236 

for  starch-sugar   by    Payen's   me- 
thod, 227,  228 

for  sugar,  by  Anthon's  latest  me- 
thod, 244 
of  starch,  24,  25 
required   by  Maubre's   method  for 

glucose,  232 

for  Landmann's  method  of  ma- 
nufacturing   starch -sugar, 
233 

Ink,  dextrine  in  making,  310 
Intervert  sugar,  159 
Iodine,  bromine,  and  chlorine,  relations 

of  starch  to,  31 
test,  233 

Johnson's  filter-press,  208 
.Jones,  Orlando,  process  for  manufactur- 
ing starch  from  rice,  128-131 

Kirchhoff's  process  for  refining  gluten 
containing  wheat-starch,  119 

Kirchhoff,  Prof.,  discovery  of  transform- 
ation of  starch  into  sugar,  153 

Krotke,  of  Berlin,  receipts  for  beer  and 
rum  couleur,  270-272,  273 

Kuhrer,  process  for  roasting  starch  for 
dextrine,  275 


Lacambre   and   Persac's   drying-room, 
74-76 

Lafferty's  centrifugal  machine,  240 

centrifugals  arranged  for  open  train 
with  vacuum  pan,  241 

La  Grange,  discovery  of  dextrine  by,  275 

Landmann's  method    of   manufacturing 
starch-syrup  and  sugar,  233,  234. 

Lassaigne's  experiments  on  dextrine,  276 

Laveur,  or  starch-washing  tank,  59 

Le   Conte's   method   for  making    corn- 
starch,  123 

Leiocome,  278 

Leiogomme,  278,  287 

Leuch's  bleaching  water,  73 

process  for  removal  of  gluten  from 
wheat-starch,  119 

Leveridge's  artificial  gum  from  potato- 
starch,  309 

Levulose,  159 

Lime   and   potash   for    refining   wheat- 
starch,  119 

Literature  of  dextrine,  277 
of  starch-sugar,  153,  155 

Liquid  syrup  or  glucose,  packing  of,  222 

Loewenhoek's  experiments  on  dextrine, 
276 

Lye,  re-use  of  weak  solution  of,  137 

Lyes,  caustic,  for  separating  starch  from 
rice,  128,  129,  131,  132,  133 

Machines  for  grating  potatoes,  52-54 
Maize,  chemical  analyses  of,  120,  121 
Le  Conte's  method  for  making,  123 
or  Indian  corn,  varieties  of,  120 
starch,  discernment  and  determina- 
tion of,  139 
in,  18,  19 

manufacture  of,  120-127 
uses  of,  120 
Maizena,  126 
Malt,  amount  which  will  liquefy  starch 

at  different  temperatures,  184 
transformation  of  starch  into  sugar 

by  means  of,  184-186 
Malting  mill,  Allsopp's,  94 
Manufacture  of  starch,  34-152 
Markl's   apparatus   for    measuring  the 

starch  in  the  tank,  59,  60 
Martin's  apparatus  for  extracting  starch 

from  wheat-flour,  111-113 
method  for  purifying  starch,  119 
for   wheat-starch    find    gluten 

from  flour,  110-113 
Mash,  washing  drum  for  separating  the 

starch  from,  96-98 
Maubre's  apparatus  for  the  manufacture 

of  glucose,  231 

method  for  manufacture  of  starch 
syrup  and  sugar,  230-233 


340 


INDEX. 


Mayet's  experiments  on   the  action  of 

caustic  potash  on  starch,  144 
Metric  system  of  weights  and  measures, 

317 
Microscope,  potato-starch  under  the,  140 

wheat-starch  under  the,  139,  140 
Mineral  substances,  starch  adulterated 

with,  149 

Mitscherlich  on  the  effect  of  fermenta- 
tion of  starch  and  fruit  sugar,  187 
Mohr's  analyses  of  grape-sugar,  258,  259 
Molasses,  want  of,  in  Europe,  154 
Mucilaginous  sugar,  production  by  means 

of  malt  or  sulphuric  acid,  165 
Musculus,    experiments   of,   on    soluble 
starch  and  globulous  dextrine,  282 
investigations  of,  on  the  transforma- 
tion of   starch   into  grape-sugar 
and  dextrine,  160-165,  172-175 

Nsegeli,  investigations  of,  on  starch,  21 

Nash's  process  for  the  removal  of  gluten 
from  wheat- starch,  117 

Nasse's  experiments  on  transformation 
of  starch  into  sugar,  156 

Nature  of  starch,  19-23 

Neutralization  by  Anthon's  method  for 

grape-sugar,  237 
process  of,  203 

Newbauer's    analyses    of    grape-sugar, 
257,  258 

Noblack   Bro.'s  &  Fritze's  glucose  fac- 
tory, Prague,  264-266 

Organization,  structure,  form,  and  size 

of  starch,  23 
Otto,  Prof.,  directions  for  manufacturing 

sugar  couleur,  273,  274 

Packing  and  transportation  of  glucose, 

222 

Paper-making,  dextrine  for,  310 
Paper,  sizing  of,  with  starch,  150 
Paste,  formation  of,  from  starch,  27,  28 
Payen's    apparatus    for    production    of 

dextrine  with  diastase,  298-300 
apparatus  for  starch-gum,  289-290 
for  the  manufacture  of  glucose, 

225,  226 
experiments  on  dextrine,  276,  277, 

278 
on  manufacture  of  chemically 

pure  dextrine,  303 
investigations   on    the  transforma- 
tion of   starch    into  grape-sugar 
and  dextrine,  165-172,  175-183 
method    for    the    manufacture    of 
starch-syrup  and  sugar,  225-230 
Pnyen,  Musculus,  and  Dubrunfaut,  de- 
ductions from  the  experiments  of,  186 


Pearly  lustre  for  bookbinders,  26 
Perfected    machinery   of  Anthon,  244- 

249 

Petiotizing  of  wine,  with  glucose,  192 
Petiot's  process  for  increasing  quantity 

of  wine,  192 
Physical  properties  of  grape-sugar,  159 

of  starch,  23,  24 

Physiological  facts  in  regard  to  saccha- 
rine compounds,  156 
Pigment  in  wheat-starch,  removal  of,  by 

ammonia,  117 
Plants,  starch  in,  17,  18 
Pliny  on  the  invention  of  starch,  17 
Pochin  and  Wooley's  patented  method 

for  manufacturing  dextrine,  291 
Polaillon    and    Maillard's    process    for 

manufacturing  wheat-starch,  114 
Polarization  of  glucose,  grape-  or  starch- 
sugar,  159 
of  starch,  23 

test  of  starch-sugar  by,  259 
Potash   and    lime    for   refining   wheat- 
starch,  119 

Potato-flour,  manufacture,  77,  78 
Potato-starch,  action  of  chemicals  on,  141 
and  dextrine  manufactory,  plan  for, 

311-316 

appearance  of,  23 

comparative  advantages  and  disad- 
vantages of,  35,  36 
difficulties   in  the  manufacture  of, 

38,  39" 
discernment  and  determination  of, 

139 

drying,  73-76 
manufacture  of,  38-78 
older  method  of  manufacture,  47 
raw  material  for,  39-47 
Voelker's  process  of  manufacture, 

47,  48 
yield  of,  76 
sugar,  155 
Potato    washing     machine,    Venuleth's, 

49-51 
Potatoes,  analyses  of,  40 

and  their  pulp — yield  of  starch,  76 
chemical  compositions  of,  40 
clearing  of,  49-51 
determining  the  amount  of  starch  in, 

40-47 
determining  the  specific  gravity  of, 

41-47 
Fesca's   scale  for  determining    the 

specific  gravity  of,  43-47 
for  potato-starch,  39-49 
table   for  ascertaining   the  specific 

gravity  of,  43 
starch  in,  19 
storing  of,  40 


INDEX. 


341 


Preserving  fruits,  263 

Pressed-out  syrup,  utilization  of,  243 

Pressure  by  Anthon's  method,  230 

Products  of  starch-sugar  manufacture, 
classification  of,  223 

Protein  compounds,  77 

Proudfoot  &  Co. 's  dextrine  factory,  Man- 
chester, England,  289 

Pulp,  uniform,  in  making  potato-starch, 
38,  39 

Pumps,  213,  215 

Pure  solid  starch-sugar  only  produced 
by  sulphuric  acid  and  boiling,  195 

Purity  of  grape-sugar,  table  for  ascer- 
taining, 261 

Putrid  fermentation,  effect  of,  93 

Pyroxilin,  22 

Quality  of  starch-sugar,   determination 

of,  256-263 

of  starch,  test  of.  144-150 
Quantitative    determination    of     grape- 
sugar,  261,  262 

Raisins,  manufacture  of  grape-sugar  and 

grape-syrup  from,  255,  256 
Ransford's    method    for    making    rice-  ! 

starch,  131,  132 

Raoult  on  the  influence  of  light  on  cane- 
sugar,  159 

Raspail's  experiments  on  dextrine,  276 
Raw  material  for  potato-starch,  39-49 

of  wheat-starch,  78-83 
starch  centrifugal  machine,  104, 105  ' 
Refining  and  bleaching  of  wheat-starch, 

methods  for,  116-119 
process  for  potato-starch,  58-71 
raw  starch,  99-105 
Regulus,  95 

Rehe's  method  for  manufacturing  rice- 
starch,  137 

Relations  of  starch  to  warmth,  water, 
acids,  bases,  alkalies,  and  diastase, 
25-31 

Remelting  by  Anthon's  method,  242 
Rice  as  a  food,  128 

ashes  of,  analysis,  127 
cultivation  of,  127 
large  contents  of  starch,  128 
origin  and  importance  of,  127 
Pay  en's  analysis  of,  127,  128 
where  cultivated,  127 
starch,  Berger's  methods  for  mak- 
ing, 132 

by  fermentation,  Berger's  me- 
thod, 132 
by   the   American   method   of  j 

manufacture,  133-135 
buildings   used    by    American 
manufacturers  of,  134 


Rice- 
starch,  Colman's method  for  making, 

132 
discernment  and  determination 

of,  139 
in,  18,19 

manufacture  of,  127-138 
Ransford's  method  for  making, 

131,  132 

Rehe's  method  for  manufactur- 
ing, 137 

Roasted  starch,  278 
Robert's  apparatus,  253 
Rossling  and   Reichardt's  apparatus  for 

the  manufacture  of  glucose,  234,  235 
Rum  couleur,  268 

Krotke's  receipt,  270-272 
Rye,  starch  in,  18,  19 

Saccharometer,  use  of  in  determining  the 

specific  gravity  of  potatoes,  43 
Saussure,  investigations  on  the  decompo- 
sition of  starch-paste,  28,  158 
on  the  souring  of  starch-paste,  33 
Scales  for  determining  the  specific  gra- 
vity of  potatoes,  43-47 
Sheibler's  hydrometer  for  ascertaining 
the  quantity  of  water  in  starch, 
146 
method  of  ascertaining  the  contents 

of  water  in  starch,  145 
Schleiden,    observations    of,    on   starch 

granules,  22 

Schmid's  analyses  of  grape-sugar,  258 
Sedimenteurs,  58,  59 
Seele's  centrifugal  machine,  70,  71 

cylinder  sieve  for  potato-starch,  55 
Separating  the  starch  from  the  fermented 

mass,  96,  97 
from  the  paste,  54-58 
Siemens's  bolting  sieve  for  potato-starch, 

56-58 

Sifting  the  starch  from  the  paste,  54-58 
Silos  for  storing  potatoes,  40 
Size  of  starch,  23 

Soda,  caustic  for  purifying  starch,  1 19 
Souring  starch  with  hydrofluoric  silicic 

acid,  294 

Sour  water,  use  of,  92 
Special  directions  for  the  manufacture  of 

starch-sugar,  225-244 
Specific  gravity  of  potatoes,  determining 

of,  41-47 

table  for  ascertaining,  43 
of  wheat-    and    potato-starch, 

141 
Starch,  action  of,  at  the  freezing  point, 

26 

apparatus  for  measuring  in  the  tank, 
59,  60 


342 


INDEX. 


Starch — 

appearance  and  value  of,  17-19 
application  of,  150-152 
bleaching  of,  71-73 
boiling  vats,  198 
chemical  formula  of,  157 
properties  of,  24-33 
chemically  pure,  characteristics  of, 

23 
chemistry  of,  17-33 

unable  to  produce  a  body  pos- 
sessing the  properties  of,,     9 
classification  of  the  various  kinds  as 

to  forms  and  sizes,  138,  139 
commercial,  vegetables  yielding,  18, 

19 
considered  as  a  nutriment  of  plants, 

22 
consists   of  granulose    and    starch 

cellulose,  22 

contents  of  in  Indian  corn,  120,  121 
corn,  first  experiments  in  making, 

122 
or  maize,  manufacture  of,  120- 

127 

decay  of,  32 
discernment   and   determination  of 

the  various  kinds,  138-144 
dry  appearance  of,  23 
extensive  diffusion  of,  in  plants,  17, 

18 

factory,  primary  conditions  for  es- 
tablishing, 36 
formation,  substance  and  nature  of, 

19-23 

from  rice,  Jones's  process  of  manu- 
facture, 128-131 
from  wheat  flour,  110-115 
from  wheat  without  grinding,  108- 

110 
granules,  formation  and  growth  of, 

21 

freeing  from  gluten,  93 
gum,  278 

or  dextrine,  indissoluble  in  al- 
cohol, 193 

Hall's  process  for  refining,  118 
history  of,  17 
in  potatoes,  determining  amount  of, 

40-47 

in  rice,  separation  of,  128-131 
in  wheat,  81 

kiln  or  drying-room,  74-76 
Kirchboff's  process  for  refining,  119 
manufacture  of,  34-152 

of,  in  United  States,  35 
manufacturing  on  a  small  scale  for 

domestic  use,  115,  116 
milk,    treatment   of,    99-105,    201, 

202 


Starch — 

milk,  treatment  of,  by  Payen's  me- 
thod, 228 
water  for,  59 
more  immediate  ingredients  of,  24, 

25 

never  pure,  25 

no  plant  that  does  not  contain,  35 
not  fermentable,  32 
organization,   structure,   form,  and 

size,  23 

paste,  decomposition  of,  28,  158 
physical  properties  of,  23,  24 
polarization  of,  23 
potato,  manufacture  of,  38-78 
pure  and  white  for  laces,  textiles, 

etc.,  118 

purifying  by  Martin's  method,  119 
refining  of,  by  ammonia,  117 

raw,  99-105 

relations  of,  to  warmth,  water,  acids, 
bases,  alkalies,  and  diastase, 
25-31 

to  iodine,  bromine,  and  chlo- 
rine, 31 

remunerative  separation  of,  18 
rice,  manufacture  of,  127-138 
separating  from  the  fermented  mass, 

96,  97 

from  the  paste,  54-58 
separation  of,  from  wheat,  83-85 
specific  gravity  of,  141 
supposed  effect  of  absence  of  light 

on  increase  of,  21 
syrup,  155,  197  ' 

and  sugar,  Landmann's  method 

of  manufacture,  233,  234 
and  sugar,    Maubre's    method 
for  manufacture  of,  230-233 
tabular  synopsis   of  the   manufac- 
ture of,  152 
technology  of,  34-152 
test  as  to  impurities  and  adultera- 
tions in,  144-150 

the  separation  of,  a  mechanical  ope- 
ration, 34 
transformation   into   dextrine   or 

starch-gum,  25 
of  into  sugar  by  means  of  malt, 

184-186 

Tucker's  process  for  purifying,  118 
value  and  percentage  of,  in  various 
species  of  grain  and  potatoes,  19 
various  colors  of,  18 
various  grains  containing,  137,  138 
yield   of  from   potatoes   and  their 

pulp,  76 

washing  tank  or  laveur,  59 
wheat,  appearance  of,  82 
sugar,  155 


INDEX. 


343 


Starch-sugar — 

advantages    over     glucose     in 
packing  and  transportation, 
222,  223 
and  cane-sugar,  action  of  yeast 

on,  178,  188 
and   dextrine,    percentages   of 

obtained,  180,  181,  183 
and  glucose,  analyses  of,  225 
and  glucose,  one  and  the  same 

product,  224 

chemical  combination  with,  189 
chemical      properties,      action 
and  decomposition   of,   187, 
188 

chemistry  of,  153-190 
determination  of  the  quality  of, 

250-263 

from  starch  by  means  of  sul- 
phuric acid,  197-225 
granulated,  252 
history,  literature,  and  termi- 
nology of,  153-159 
in  commerce,  different  forms  of, 

197-225 

in  dextrine,  testing,  305 
ingredients  for  manufacture  of. 

201 
manufactory,  description   of, 

264-266 

manufacture,  153-267 
refined,  solid,  197 
special  directions  for  the  manu- 
facture of,  225-244 
technology  of,  191-267 
where  principally  produced  in 
Europe  and  the  United  States, 
154 

£team  jet  condenser,  vacuum,  219 
Steamed  gum,  278 
Steeping  and  bruising  the  wheat,  86-91 

troughs  for  wheat,  86 
Stiffening  power  of  wheat-  and  potato- 
starches,  141 
Stirring  tub,  199 

Structure,  form,  and  size  of  starch,  23 
Substance  and  nature  of  starch,  19-23 
Sugar-coloring,  263 
Sugar  color,  manufacture  of,  268-274 
common  solid  starch-,  197 
granulated  starch-,  197 
grating  machine,  252 
maximum  which  may  be  obtained, 

181 

starch-,  manufacture  of,  153-267 
wherein  found,  and  in  what  percent- 
age, 155-1 o7 

yield  of,  from  grapes,  256 
Sulphate  of  zinc  or  copper,  starch  adul- 
terated with,  testing,  148 


]  Sulphuric  acid,  production  of  dextrine 
and  starch-sugar  with,  165 

relative  quantity  used,  194 

removal  of,  from  the  starch- 
sugar  by  carbonate  of  lime, 
203 

use  of,  in  producing  starch- 
sugar,  196,  197-225 

Sulphurous  acid,  use  of,  for  procuring 
the  whitest  possible  color  for 
sugar,  243 

for  suppressing  putrefaction, 
137 

use  of,  in  separating  starch 
from  maize,  123 

Taylor's  bag-filter,  207,  -237 
Technology  of  dextrine,  283-315 
of  starch,  34-152 
of  starch-sugar,  191-267 
Temperature,    regulating    the,    in    the 

manufacture  of  dextrine,  284 
Terminology  of  starch-sugar,   153-155, 

156 

Terra  alba,  starch  adulterated  with,  149 
Test  as  to  the  impurities  and  adultera- 
tions in  starch,  144-150 
as  to  transformation  of  starch  into 

sugar,  233 
Testing  of  dextrine  as  to  impurities  and 

adulterations,  304-309 
of  starch,  138-144 
Thermometers  and  hydrometers,  329 
Tincture  of  sugar,  268 
Transformation   of  starch   into  glucose 

and  dextrine,  process  of,  159-187 
[  Transformation    of    starch    or  dextrine 
into  sugar,  never  complete  and  per- 
fect, 194 
I  Trees,  starch  in  the  wood,  trunks,  and 

bark  of,  1 8 

Tucker's   process  for  purifying  starch, 
118 


Utilization  of  the  pressed-out  syrup,  243 
United  States,  corn-starch   manufactu- 
rers in,  124 
species   of  starch   applied  in, 

for  starch-sugar,  197 
Uric  sugar,  155 

Vacuum  apparatus,  216,  217 

attainable,  220 

pans,  Lafferty's,  241 

pump,  Guild  &  Garrison's,  215,  216 

steam  jet  condenser,  219 
Value  and  appearance  of  starch,  17-19 
Venuleth's  potato  washing  machine,  49- 

51 
Vinegar  coloring,  273 


344 


INDEX. 


Vogel.  observation  of,  on  starch,  26 
Vogel's    experiments    on    production  of 
dextrine  from  wood,  300 

Water,  amount  of,  in  air  dried  wheat, 

81,  82 

clear  syrup-,  249 
influence  of,  on  the  appearance  of 

starch,  37 
in  starch,  24,  144-147 

table  for  ascertaining,  146 
relations  of  starch  to,  25,  27,  28 
which  will  dissolve  grape  and  cane- 
sugars,  188 
Washing-drum    for     separating     starch 

from  the  mash,  96-98 
Washing  or  sifting  starch  from  the  paste, 

54-58 

potatoes,  49-51 

Watts's  process  for  manufacturing  corn- 
starch  by  fermentation,  123 
Weights  and  measures,  319 
metric  system,  317 
Wet  air-pump,  213,  214 
Wheat,    advantage    of    grinding  before 

steeping,  96 
amount  of  water  in  air-dried,  81, 

82 

analyses  of,  82 

and  potato-starches,  stiffening  pow- 
er of,  141 

ashy  substances  in,  82 
chemical  composition  of,  82 
duration  of  fermenting  process  for, 

92 
fermenting  the  bruised  ground-up, 

91-96 

flour,  starch  from,  110-115 
gluten  in,  81 
grain,  structure  of,  80 
gum  in,  82 

hard,  glassy,  or  steel-like,  79 
mill  or  grain  crusher  for,  89-91 
semi-hard  or  medium  soft,  79 
separation  of  starch  from,  83-85 
steeping  troughs  for,  86 
soft  or  white,  79 
steeping  and  bruising,  86-91 
the  germ  or  embryo  of,  81 


Wheat- 
starch,  action  of  chemicals  on,  140 
adulterated    with     flour-     and 
potato-starch,    and  gypsum, 
148,  149 

advantages  of,  36 
appearance  of,  82 
discernment  and  determination 

of,  139 

Fesca's  new  method  of  manu- 
facture, 114,  115 
in,  18,19 

manufacture  of,  78-119 
methods  for  refining  and  bleach- 
ing, 116-119 
Polaillon  &  Maillard's  process 

of  manufacture,  114 
process   by  acetous  fermenta- 
tion, 85 

process  of  drying,  105-107 
raw  material  of,  78-83 
various  methods  of  producing, 

84 

without  fermentation,  107 
without    grinding   the    wheat, 

108-110 

Whiskey  couleur,  268 
White  sugar  obtained  by  use  of  sulphur- 
ous acid,  243 
Wine,  effect  of  starch  on,  23 

starch-sugar  for  improving,  191,  192 
Wines,  improvement  of,  by  grape-sugar, 

263 

Wood,  experiments  for  producing  dex- 
trine from,  300-302 
fibre,  extracting  from  the  wood.  165 

Xylodin,  22 
Xylon,  22 

Yeast,   action    of,    on    cane-sugar    and 

starch-sugar,  187,  188 
on  solutions  of  grape-sugar,  1 88 
in  the  production  of  starch- sugar, 

165 
Yellow  pigment,  extracting  from  starch, 

72,  118 

Yield  of  starch  from  potatoes  and  their 
pulp,  76 


INCREASE  TO 
DAY    AND     T0     ,1° 

OVERDUE 


PENALTY 
°N  THE  F°"RTH 
SEVENTH     DAY 


MAR  31  J93 


AUG13I985 

RECEIVED  BY 

JUl  1  7 

t^COLATION 


APR   14  1935 


MAR  22  1939 


AU6  4    1941 
SEP   25  1942 


DEC    9    194? 


YC   18889 


GENERAL  LIBRARY  -  U.C.  BERKELEY 


UNIVERSITY  OF  CALIFORNIA  LIBftAfcY 


